THE A2 DIVE COMPUTER – DESIGNED FOR EVERYDAY LIFE AND DIVING.
Welcome to SCUBAPRO dive computers and thank you for purchasing the A2. You are now
the owner of an extraordinary partner for your dives and everyday life. This manual provides
you with easy access to SCUBAPRO state-of-the-art technology and the A2’s key features
and functions. Should you wish to know more about SCUBAPRO diving equipment, please
visit our website www.scubapro.com
IMPORTANT
Before using your SCUBAPRO A2, please carefully read and understand the Read First booklet that
is included in the package.
English
• The A2 has a depth rating of 120m/394ft.
• At depths between 115m/377ft and 120m/394ft in Dive mode the A2 provides alerts about the
maximum depth, and at depths over 120m/394ft the A2 automatically switches to Gauge mode and
cannot be used as a decompression computer for the remaining time of the dive.
• Diving at oxygen partial pressures higher than 1.6bar (corresponding to a depth of 67m/220ft when
breathing compressed air) is extremely dangerous and could lead to serious injury or death.
• Never risk your life on only one source of information. Eventually, every computer has the potential
to fail, so do not depend exclusively upon it and always have a plan for how to handle failures. Use
a redundant dive computer, carry backup tables and depth/time instrumentation.
The A2 is delivered in deep sleep mode where the display is off. You must activate the A2 with a
press-and-hold of the SEL/ESC button before the rst dive.
The A2 dive instrument is also compliant with the European Union directive 2014/30/EU.
Standard EN 13319: 2000
The A2 dive instrument is compliant with the European standard EN 13319: 2000 (EN 13319: 2000 – Depth gauges and
combined depth and time measuring devices – Functional and safety requirements, tests methods).
A2 USER MANUAL
WARNING
WARNING
The A2 dive instrument is a personal protective equipment in compliance with the essential safety requirements
of the European Union Regulation 2016/425. RINA SpA, Via Corsica 12, I-16128 Genoa, notified body no.
0474, have certified its conformity with the European Standard EN 250: 2014 (EN 250: 2014 : Respiratory
equipment – Open circuit self-contained compressed air diving apparatus – requirements, testing and marking);
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TABLE OF CONTENTS
1. INTRODUCTION TO THE A2 ................................................................................... 8
1.1 Switching on the A2 ......................................................................................... 8
1.2 The watch screen ............................................................................................. 8
9. INDEX ..................................................................................................................... 88
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1. INTRODUCTION TO
THE A2
Your A2 user manual is divided into the
following main chapters:
Introduction to the A2. This chapter
provides an overview of the A2 dive computer
and describes its operating modes and main
functions when on the surface.
A2 as an everyday watch. This chapter
describes the A2’s operation when it is
used as a watch.
A2 settings and menus on the surface. This
section goes through the settings of your A2.
Diving with the A2. This section takes you
underwater with the A2 and describes all
settings and functions of the A2 as a dive
computer. It outlines everything the A2
can—and will—do to enhance your safety
and fun underwater.
Interfaces for the A2 and an
introduction to LogTRAK. This section
describes how to download data, change
settings, and manage your logbook.
A2 accessories. This chapter briey
describes the extras that can be purchased
as additional options to get the most of
your dive computer in all diving conditions.
Taking care of your A2. This chapter
describes how you should take care of your
A2 after underwater adventures, and also
summarizes the main technical information
of this instrument.
The A2 is a technologically-advanced
instrument that can accompany you
during your underwater adventures while
providing you with accurate depth, time
and decompression information. On
the surface its size makes it your ideal
everyday companion. With features such
as wake-up alarm, dual time, stopwatch,
barometer, altimeter and swim mode, the
A2 can tackle almost every possible task.
The buttons allow you to initiate operating
functions, make setting changes and
access menus while on the surface. During
the dive they show additional information
on the computer screen and activate the
backlight.
Now it is time to dive into the details. We
hope you will enjoy getting to know your
new computer and we wish you many
happy dives with the A2.
1.1 Switching on the A2
The A2 is delivered to you in a deep sleep
mode. This is done to preserve battery life
and to ensure your A2 arrives with a fresh
battery.
In order to switch on the A2 for the rst
time you need to press-and-hold the SEL/
ESC button (lower left). After this initial
activation, the A2 will never again return to
deep sleep mode.
1.2 The watch screen
When the A2 is switched on the rst time
the display screen shows the time and date
as follows:
The time and date values, along with the
format, can be changed to your liking. This
is described in chapters 2.1.6 Display
design and 2.1.7 Time format.
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1.3 A2 buttons
The functions of the buttons on the
surface are summarized in the table below
and explained in detail in the following
sections.
“LIGHT”
button,
Top Left:
“SEL/ESC”
button,
Bottom
Left:
“+/UP”
button,
Top Right:
“-/DOWN”
button,
Bottom
Right:
Press = backlight
Press-and-hold = launch
compass
Press = select (access main
menu and submenus or
conrm selection / setting)
Press-and-hold = escape
(return to previous menu or
cancel the setting); from the
main time and date display
shows the current gas
settings
Press = adds numerical
values, toggles up to the
previous menu
Press-and-hold = from the
main time and date display
shows the selected dive
mode; from the selected dive
mode display activates the
swim mode
Press = subtracts numerical
values, toggles down to the
next menu
Press-and-hold = from the
main time and date display:
shortcut to dive ready mode
which shows the main dive
settings
1.4 Button lock
A simultaneous press-and-hold of the SEL/
ESC and -/DOWN buttons will lock the
main time and date display. Once locked,
by pressing just the SEL/ESC button the
following screen will be displayed:
Unlock the display by simultaneously
pressing-and-holding the SEL/ESC and -/
DOWN buttons again.
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1.5 Bezel markings and symbols
In this section the markings and symbols on the A2’s outer and inner bezel as well as on its
display are explained in detail.
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1No-y symbol
2Planner menu indicator
3+/UP button
4Logbook menu indicator
5Water contact
6Active tank pressure indicator bar
7Dive menu indicator
8-/DOWN button
9Settings menu indicator
10 Low battery symbol
11 Altitude symbol
12 Heart rate detection symbol
13 Gas menu indicator
14 SEL/ESC button
15 Sport menu indicator
16 Ascent speed / N2 bar
17 Bluetooth menu indicator
18 Light button
19 Navigation menu indicator
20 No-dive symbol
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1.6 Battery
The A2 uses a CR2450 battery type.
The A2 will alert you when the battery is
approaching a critical discharge level by
displaying the battery symbol.
A steady symbol means that the battery is
low, with some reserve left. At this point the
backlight cannot be activated. If the symbol
blinks, the battery level is dangerously low
and the backlight and alarm tones cannot
be activated; diving is not recommended
before replacing the battery.
WARNING
Starting a dive when the battery symbol is
blinking can cause the computer to fail during
the dive! Replace the battery before any diving
activity if the blinking battery symbol appears.
When the “no-dive” symbol appears with the
battery symbol, the A2 cannot be used for
diving until a fresh battery is installed.
Please refer to chapter 3.1.4 Checking
the battery status for details on how to
manually trigger the battery level check.
WARNING
The A2 will not start a dive if the battery has
reached the critical level indicated by the
battery symbol. In this state the A2 cannot be
used for diving.
WARNING
When your A2’s battery reaches the end of its
lifetime, it is recommended that it be replaced
by an authorized SCUBAPRO service center.
1.7 Operation modes
The A2’s different modes are shown on the
dial ring of the computer and the current
function mode is indicated with an arrow.
Each mode may have sub functions and
menus. By pressing the SEL/ESC button
you activate the mode and as an indication
the arrow starts blinking.
The modes are grouped and described in
this manual in four chapters:
1. A2 as an everyday watch.
2. A2 settings and menus.
3. A2 as a dive computer.
4. Bluetooth interface of the A2 and an
introduction to LogTRAK.
The A2 has two main operation modes:
1. Watch mode. The display is on and
shows the time and date (in various
formats). From this mode other surface
operation modes can be selected:
a. Sport mode
b. Bluetooth communication mode
c. Compass
d. Altimeter
e. Dive planner
f. Logbook
As well as settings can be changed:
a. Dive settings
b. User settings
c. Gas settings
2. Dive mode. This mode is activated
when the computer reaches a depth of
0.8m/3ft or more. In this mode the A2
monitors depth, time, temperature and
decompression.
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The following chart describes the main menu structure:
TIME
& DATE
DIVE
LOGBOOK
PLANNER
NAVIGATION
BLUETOOTH
SPORT
GAS
RETURN
SETTINGS
Logbook
pages
DOWN
DOWN
DOWN
UP
UP
UP
UP
DOWN
DOWN
DOWN
DOWN
DOWN
UP
UP
UP
UP
SEL
Planner
pages
Compass
settings
Bluetooth
connection
Sport settings
Dive settings
& menus
User settings
Gas settings
SEL
SEL
SEL
SEL
SEL
SEL
SEL
ESC
ESC
ESC
ESC
ESC
ESC
ESC
ESC
SEL
ESC
ESC
DOWN
UP
TIME & DATE
Dive settings
& menus
User settings
Gas settings
Sport settings
Bluetooth
connection
12
Compass
settings
Planner
pages
Logbook
pages
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1.8 Basic settings
The initial activation of your A2 requires
some basic set-up (setting time and date,
units, etc.).
1.8.1 Time and date settings
Starting from the
main time and date
display, pressing the
SEL/ESC button
takes you to the
main menu.
English
After the minutes
are conrmed
the date can be
adjusted the same
way.
From the main
menu toggle down
to Settings with
the -/DOWN button
then press SEL/
ESC.
From the Settings
menu toggle down
to Watch then
press SEL/ESC.
From the Watch
menu toggle down
to Set Time then
press SEL/ESC.
By pressing +/UP
or -/DOWN you can
select the hours
and conrm them
by pressing SEL/
ESC. The minutes
can be set the
same way.
There are additional watch settings that
you can adjust to your liking. These are
described in chapter 2.1 Clock setting
functions.
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1.8.2 User settings
WATCH
ALARM
SET UTC 1
SET UTC
2
SET TIME
SET DATE
DESIGN
FORMAT
RETURN
DOWN
UP
DOWN
UP
UP
UP
UP
UP
UP
DOWN
DOWN
DOWN
DOWN
DOWN
SEL
ESC
ESC
DOWN
UP
The user-related settings (backlight
duration, display contrast, units, etc.) can
be selected with a press-and-hold of the
SEL/ESC button which returns you to the
previous submenu.
For example, from
the Settings menu
toggle down to
User then press
SEL/ESC.
From the User
menu toggle down
to Units then press
SEL/ESC.
Now the various
units can be
selected. These
selections are
effective in all
operating modes;
for example, during
diving your depth
can be shown in
meters or in feet.
2. A2 AS AN EVERYDAY
WATCH
The A2 is more than just a watch. It features:
• Stopwatch with lap time and 72 hours
of run time.
• Swim stroke and distance counter.
• Navigation compass.
• Altimeter for tracking your excursions to
the mountains.
• Thermometer and barometer for current
weather conditions.
• Heart rate monitor function.
• Wireless air integration.
• Step counter / activity tracker.
• Wake-up alarm function.
• Dual time.
2.1 Clock setting functions
Starting from the main time and date
display, press the SEL/ESC button to enter
the main menu.
From the main menu, toggle down to
Settings with the -/DOWN button, then
press SEL/ESC. From the Settings menu
select Watch to enter the clock settings.
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2.1.1 Setting the alarm clock
From the Watch menu press the SEL/
ESC button to enter the Alarm submenu.
Here you can activate or deactivate the
alarm clock by pressing the +/UP or -/
DOWN buttons. Selecting ALARM ON
will allow you to set the time of the alarm.
You can scroll the hours by pressing +/UP
or -/DOWN buttons. Pressing SEL/ESC
will conrm the hour setting and switch
to minutes. You can scroll the minutes
by pressing +/UP or -/DOWN buttons.
Pressing the SEL/ESC button will conrm
the minutes setting and activate the alarm.
2.1.3 Setting UTC 2
Dual time uses the same “base time” as
the main clock. Therefore, adjusting the
time as described in section ‘Setting the
time’ will also inuence the dual time. The
dual time zone selection will dene the
difference to the main clock time. When the
time zone selection is OFF, then the dual
time is disabled. When pressing the SEL/
ESC button the UTC 2 time hours will be
highlighted. You may change the setting
by pressing the +/UP or -/DOWN buttons
in a range of +14h to -13h or by selecting
OFF. By pressing the SEL/ESC button,
the minutes will be highlighted and you
may edit them using the +/UP or -/DOWN
buttons in 15-minute increments. The UTC
2 setting will be conrmed by pressing the
SEL/ESC button.
English
2.1.2 Setting UTC 1
The UTC setting will change the displayed
time compared to Greenwich 0-Meridian.
This feature is practical when traveling
through different time zones. By pressing
SEL/ESC you may edit the hours with +/
UP or -/DOWN buttons in a range of +14h
to -13h. By pressing SEL/ESC the minutes
will be highlighted and you may edit them
with +/UP or -/DOWN buttons in 15-minute
increments. The UTC 1 setting will be
conrmed by pressing the SEL/ESC button.
A2 USER MANUAL
2.1.4 Setting the time
By pressing the SEL/ESC button in the
Set Time submenu the time setting will be
activated. You may change the hours with
+/UP or -/DOWN buttons. By pressing the
SEL/ESC button the selection will change
to minutes and can be edited. The new
time setting will be conrmed by pressing
the SEL/ESC button.
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NOTE: seconds cannot be edited;
F
they always start counting from 0.
2.1.5 Setting the date
By pressing the SEL/ESC button in the
Set Date submenu the rst two digits will
be highlighted. You may change them by
pressing the +/ UP or -/DOWN buttons.
Change the selection to the next two digits
by pressing the SEL/ESC button. Finally,
set the year by pressing +/ UP or -/DOWN
and conrm the date with the SEL/ESC
button. In 24h time format the rst digits in
the date are days, in AM/PM time format
the month is rst. You can toggle between
24h and AM/PM in the Format submenu.
2.1.6 Display design
In this menu you may select the design of
the main time and date display to suit your
personal preferences by scrolling through
the options with the +/ UP or -/DOWN
buttons. Conrm your selection by pressing
the SEL/ESC button. In the following
screens the display design selection is
shown next to how the layout is presented
on the main watch display screen.
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2.1.7 Time format
SPORT
S-WATCH
TRAINING
SWIM
APNEA
SEL
ESC
ESC
DOWN
UP
DOWN
DOWN
UP
UP
DOWN
UP
STEPCOUNTER
UP
DOWN
RETURN
UP
DOWN
Choose your preferred time format by
scrolling with the +/ UP or -/DOWN
buttons, press the SEL/ESC button to save
your settings. You can choose between
AM/PM or 24-hour format.
NOTE: Time format will also change
F
the date format: MM/DD/YY in AM/
PM mode and DD/MM/YY in 24h
mode. This change will take place, for
example, in watch mode, logbook, etc.
2.2 Sport mode
Starting from the main time and date
display, press the SEL/ESC button to enter
the main menu, then toggle down to Sport
and press the SEL/ESC button again to
enter the Sport menu. In this menu sportrelated functions like swim stroke counter,
stopwatch or activity counter (training) can
be activated.
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A2 USER MANUAL
The functions of the buttons in Sport
mode are summarized in the table below
and explained in detail in the following
sections.
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“LIGHT”
“SEL/ESC”
“+/UP”
“-/DOWN”
Press = backlight
Press-and-hold in Swim
mode = launch the compass
Press-and-hold in
Stopwatch mode = returns
to the main time and
date display (stopwatch
will still be running in the
background)
Press in Swim mode =
stops/restarts timer
Press-and-hold in Swim
mode = ends swim exercise
Press in Stopwatch mode =
returns to Sport menu
Press-and-hold in
Stopwatch mode = returns
to Sport menu
Press in Training mode = set
bookmark
Press = scrolls through the
alternative displays
Press-and-hold in Swim
mode = ends swim exercise
Press in Stopwatch mode =
manually start/stop timer
Press-and-hold in Stopwatch
mode when timer stopped =
reset timer to zero
Press-and-hold in Training
mode = stops/restarts timer
Press = scrolls through the
alternative displays
Press in Stopwatch mode
when timer stopped = scrolls
through laps
2.2.1 Stopwatch
From the Sport menu press SEL/ESC to
enter the Stopwatch submenu.
The stopwatch will start measuring the time
by pressing the +/UP button.
To pause the time on the stopwatch press
the +/UP button once again. To reset the
time to 0 press-and-hold the +/UP button
while the stopwatch display shows the
status STOPPED.
In addition to time, laps can be marked
by pressing the -/DOWN button while the
stopwatch is running. By doing so the lower
part of the screen will show the number of
the lap while the lap time will be displayed
in the upper part of the screen. While the
stopwatch is stopped you can review your
lap times from the memory by repeatedly
pressing the -/DOWN button.
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By pressing-and-holding the SEL/ESC
button you can exit the stopwatch and
return to the Sport menu.
NOTE: You can leave the stopwatch
F
actively counting or you can leave
the stopped time on the display.
The status will be stored in memory,
allowing you to continue from the
same display at a future time.
Air pressure in
millibars.
English
2.2.2 Training mode
From the main menu toggle down to Sport
and press SEL/ESC to enter.
Pressing the SEL/ESC button in the
Training submenu will start the exercise. A
press-and-hold of the same button will end
the exercise.
In the middle row the time is counting. The
counter can be stopped and restarted by
a press-and-hold of the +/UP button. The
current time is displayed on top, stop timer
in the middle, temperature in the bottom
left and the heart rate in the bottom right
of the screen.
Total ascent during
the exercise
Altitude difference
during the exercise
Current altitude.
Minutes per 1000
repetitions.
The information in the middle row can be
scrolled through by pressing the +/UP or -/
DOWN buttons. A press of the +/UP button
will change the top row information in the
following order:
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Repetitions per
minute.
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Step (repetition)
count during
current exercise.
NOTE: Since the A2 is worn on
F
the wrist, it is counting repetitive
movements from its internal sensors
in Sport mode. The A2 is not a pure
step counter since arm movements
may count as repetitions as well. The
A2 is also not an activity band since
only same-direction movements are
counted.
NOTE: Refer to chapter 3.5.2 Step
F
counter statistics to learn how
to review your weekly or monthly
statistics from the logbook.
2.2.3 Swim mode
Swim mode combines a stopwatch with
a stroke and distance counter. For proper
counter operation the user’s pending values
can be adjusted. These are described in
chapter 3.1.2 Swim settings.
in the bottom left of the display. When the
heart rate function is activated, the values
will be displayed in the bottom right corner
of the screen. Switch between displays by
pressing the +/UP or -/DOWN buttons. A
press of the SEL/ESC returns you to the
Sport menu.
NOTE: Swim mode stays active in
F
shallow water down to 3 meters. This
allows ip turns in pool and horizontal
dives. An immersion deeper than 3
meters will start a dive in the mode
which is selected in the A2 (SCUBA,
APNEA or GAUGE).
2.2.4 Apnea mode
Apnea exercise mode can be activated
from the Apnea menu. The session starts
with a surface interval.
Apnea mode settings are described in
chapter 3.2.3 Apnea mode settings.
Display information and diving with this
mode is described in chapter 4.1.2.3
APNEA mode.
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When the swim mode is activated, the
duration of your swim will be shown on
the second screen. The distance will be
displayed on the third screen and the
last screen will show the number of swim
strokes. The water temperature is shown
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2.2.5 Enabling the activity counter
NAVIGATION
COMPASS
RETURN
ALTIMETER
DOWN
UP
SEL
ESC
ESC
UP
UP
DOWN
DOWN
COMPASS
BEARING
DECLINATION
TIMEOUT
CALIBRATION
SEL
ESC
UP
DOWN
UP
UP
UP
DOWN
DOWN
DOWN
ESC
RETURN
UP
DOWN
The A2 has a step counter that can be
switched on in order to count your daily
activity. This functionality is running in the
background of the A2’s normal watch
operation. During diving the activity counter
is deactivated.
2.3 Navigation
From the main menu toggle down to the
Navi submenu and enter by pressing the
SEL/ESC button. In this section compass
related settings as well as information about
the altitude, barometric and temperature
values can be selected.
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A2 USER MANUAL
If the A2’s step counter is enabled in the
background (ON), you can set the LCD
display to switch off when there is no
motion detected. The time after the display
would switch off can be set from 1 to
240 minutes or you can set the display to
stay active even when there is no motion
detected by selecting “never” in this menu.
NOTE: If you do not wish to track
F
your daily activity with the A2, you
can disable the activity counter by
selecting OFF in this menu. This
will also help preserve the battery’s
lifetime.
NOTE: Refer to chapter 3.5.2 Step
F
counter statistics to learn how to
review your daily, weekly or monthly
statistics from the logbook.
2.3.1 Using, calibrating and setting
the compass
In this section compass related settings are
described in detail. The different settings
can be selected in the following submenus:
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2.3.1.1 Bearing
By pressing the SEL/ESC button the
compass will be launched and show the
bearing direction (12 o’clock on the watch)
in the middle row in degrees.
2.3.1.2 Declination
A compass points to the magnetic north
pole of the earth. Geographic and magnetic
north poles are corrected with a declination
setting. Declination depends on your
current location on the earth.
By pressing the SEL/ESC button the
declination value will be highlighted. By
pressing the +/UP or -/DOWN buttons
you can select the value from -90 to 90°
in 1° increments. By pressing SEL/ESC the
value will be conrmed.
2.3.1.3 Timeout
Compass timeout is the amount of time
the compass is displayed when activated.
Compass timeout is valid for the display
of the compass in all modes: Dive, Sport,
etc. You can adjust the timeout setting by
pressing SEL/ESC and scrolling the values
by pressing the +/UP or -/DOWN buttons
between 5, 10, 15, 30 and 60 seconds or
PUSH (on/off). By pressing the SEL/ESC
button the value will be conrmed.
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2.3.1.4 Recalibration
1. PLACE
HORIZONTALLY
2. ROTATE
HORIZONTALLY
3. PLACE
VERTICALLY
4. ROTATE
VERTICALLY
5. READY
CALIBRATION
SEL
SEL
SEL
SEL
SEL
SEL
NOTE: The compass must be
F
recalibrated after each battery change
or when traveling to a location where
the earth’s magnetic eld strength is
different.
English
A2 USER MANUAL
By pressing the SEL/ESC button the
recalibration process will start.
1. Place horizontally. Hold the A2 so
that its display points upwards. Press
the SEL/ESC button.
2. Rotate horizontally. Rotate the A2 at
least 180° horizontally. Press the SEL/
ESC button.
3. Place vertically. Hold the A2 so that
its display points sideways. Press the
SEL/ESC button.
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4. Rotate vertically. Rotate the A2 at
least 180° vertically. Press the SEL/
ESC button.
5. Calibration ready. The A2’s
3D compass recalibration is now
complete.
2.3.2 Reading the altitude,
barometric and temperature
values
In the Navigation (Navi) menu toggle
down to Altimeter (Altimtr) and press the
SEL/ESC button to enter. In this submenu
on the rst display the current altitude
(in meter or feet) is calculated from the
barometric pressure and shown in the
middle of the screen. The temperature (in
Celcius or Fahrenheit) and air pressure (in
mbar) at your current altitude are displayed
in the bottom left and bottom right of the
screen, respectively.
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NOTE: Barometric pressure is a
F
variable, changing with weather and
atmospheric pressure at a particular
elevation. The Dive algorithm uses
Altitude Classes which are directly
derived from the barometric pressure.
Altitude is counted from the current
barometric pressure and is therefore a
relative value.
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By pressing the +/UP or -/DOWN buttons
WATCH
USER
SWIM
SOUND
BATTERY
RETURN
SETTINGS
DOWN
UP
SEL
ESC
ESC
UP
UP
UP
UP
UP
DOWN
DOWN
DOWN
DOWN
DOWN
you can switch to an additional display
where the atmospheric pressure at sea
level is shown.
The altitude can be adjusted when current
elevation is known by pressing the SEL/
ESC button. The new altitude value will
be highlighted in the center of the screen.
By pressing +/UP or -/DOWN buttons
the value can be adjusted in 10m/50ft
increments.
This Barometer feature allows you to
foresee approaching weather in the
upcoming hours if your altitude remains the
same.
3. A2 SETTINGS AND
MENUS ON THE
SURFACE
In this chapter the settings that can be
completed on the surface are described.
These settings will allow you to personalize
your A2 as desired.
3.1 General settings
In the Settings menu the following
functions can be set:
• Watch settings – please refer to chapter
2.1 Clock setting functions.
• User settings – workload, backlight,
display contrast, units, owner info,
desaturation reset, service check,
current software version.
• Swim settings – swim heart rate, swim
stroke depth and length.
• Sound settings – enable or disable
button beeps, dive warnings.
• Battery – check battery status.
English
A2 USER MANUAL
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3.1.1 User settings
USER
LIGHT
CONTRAST
UNITS
OWNER
DESATURATION
RETURN
DOWN
UP
UP
UP
UP
UP
UP
SEL
ESC
DOWN
DOWN
DOWN
DOWN
DOWN
ESC
WORKLOAD
UP
DOWN
UP
DOWN
SERVICE
This section allows you to customize your
A2 to your liking. Settings like backlight
duration, display contrast and units can be
changed here.
ADT model is changed accordingly. This
menu allows you to select the workload
base or switch off the workload estimation,
in which case your A2 will behave like the
SCUBAPRO dive computer models without
heart rate or air integration.
In the workload menu you can scroll the
parameters which are used to measure
your workload during the dive by pressing
the +/UP or -/DOWN buttons. If you select
the heart rate by pressing the SEL/ESC
button, the heart rate limits can be edited.
The base level indicates your average light
moving heart rate limit and the maximum
heart rate is what you can reach under
extreme exercise. Select the values with +/
UP or -/DOWN and conrm with the SEL/
ESC button.
26
3.1.1.1 Workload
At the base of any decompression
calculation there is the transport of nitrogen
from the lungs to the blood and from there
to the tissues during on-gassing, and the
same but in reverse during off-gassing.
As such, it is obvious that the single most
important parameter in a decompression
calculation is the rate at which blood
travels through the body. During heavy
exercise, the total blood ow from the heart
can be up to 4 times higher than while at
rest. This increase in blood ow is rather
unevenly distributed, with some tissues
such as the Central Nervous System and
the brain being unaffected, while others like
the muscles receiving up to 10 times more
blood than when at rest.
The A2 estimates workload based on heart
rate or changes in breathing pattern from
the high-pressure transmitter, and the
decompression calculation in the ZH-L16
SCUBAPRO recommends using the
workload and Heart Rate features on all
dives, but especially when making technical
dives. When the dive goes as planned
there is no effect to the decompression
schedule. However, when workload is
high more decompression time will be
required. Adaptive algorithm additionally
incorporates into the calculation the water
or skin temperature (only with the patented
SCUBAPRO Heart Rate belt) and micro
bubble formation.
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3.1.1.3 Contrast
In the User submenu toggle down to
Contrast and press SEL/ESC to access
the display contrast settings. Contrast can
be set from 0 up to 15 using +/UP or -/
DOWN and saved with another press of the
SEL/ESC button.
English
You can also select the workload to be
measured from breathing by selecting the
“respiratory” or a combination of heartrate
and breathing where both parameters
are measured and the higher or lower
parameter is used by the algorithm.
When heartrate is not selected as a
workload parameter, the heart rate monitor
can be still shown in the screen during
diving. This can be selected at the lower
eld where HR can be selected to be ON or
OFF. Conrm the selection by pressing the
SEL/ESC button.
3.1.1.2 Backlight
In the User submenu press SEL/ESC to
access the backlight settings. The duration
of the backlight can be set from 5 up to 30
seconds using +/UP or -/DOWN buttons
and saved with another press of the SEL/
ESC button.
3.1.1.4 Units
Different combinations of temperature, air
pressure and height or depth measurement
units can be selected in the Units submenu.
NOTE: Setting units can be completed
F
directly in your A2’s Units submenu
or on your PC/MAC and personal
hand held device using the program
LogTRAK. For further guidance on
how to set units with LogTRAK, please
refer to chapter 5.2.5 Setting units in
LogTRAK.
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3.1.1.5 Owner information
You can input owner’s information using
the LogTRAK program. This function is
described in detail in chapter 5.2.4 Writing
owner information with LogTRAK.
3.1.1.6 Desaturation reset
When the A2 is still counting down the
desaturation, some menu changes are
not possible. In the event you decide to
reset the desaturation, the safety code
313 must be entered. This procedure
prevents unwanted resetting and stores
the desaturation reset in memory (in the
next dive log the desaturation symbol will
be shown).
By pressing the SEL/ESC button in the
Desat submenu, the code page appears.
The rst digit will be highlighted, and can
be edited by pressing the +/UP or -/DOWN
buttons. By pressing the SEL/ESC button
the number is conrmed and the next
number will be highlighted. When the code
is entered correctly and then conrmed
by pressing the SEL/ESC button, the
desaturation reset is complete.
WARNING
Resetting desaturation will affect calculations
of the algorithm which may lead to serious
injury or fatal issue. Do not reset desaturation
without having a very good reason.
3.1.1.7 Service Information
The date of the last service by an
authorized SCUBAPRO dealer is shown in
this submenu.
NOTE: Only an authorized SCUBAPRO
F
service center, which has the proper
tools and instruments, can reset the
service date. The service date is only
set after the A2’s seals are checked
and veried.
Pressing the +/UP button from the “last
service” screen shows the current software
version of the A2. You can download the
latest version from the SCUBAPRO website,
see chapter 5.2.6 Updating your A2.
28
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By pressing +/UP from the “software
SWIM
SWIM HR
DEPTH
LENGTH
RETURN
SEL
ESC
UP
DOWN
UP
UP
UP
DOWN
DOWN
DOWN
ESC
version” screen the Bluetooth version
information will be displayed.
3.1.2 Swim settings
Next on the Settings menu listing is Swim.
Press the SEL/ESC button to enter.
NOTE: The A2’s heart rate monitor
F
function is only compatible with the
patented SCUBAPRO heart rate belt.
3.1.2.2 Swim stroke depth and
length
For the swim stroke counter you must set
the cycle threshold — how much depth
difference is counted as a stroke cycle,
as well as the distance per cycle (stroke
length) — in order to achieve proper results.
The following illustration shows the
parameters:
English
3.1.2.1 Swim heart rate
By pressing the SEL/ESC button in the
swim heart rate menu you can choose if
you want your heart rate monitored during
the swim exercise. Select ON or OFF by
A2 USER MANUAL
pressing +/UP and conrm your selection
by pressing the SEL/ESC button.
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Stroke length
Stroke depth
By pressing the SEL/ESC button in the
Swim menu, you reach the swim mode
settings. By pressing the SEL/ESC button
the counter stroke threshold (rst depth,
then length) will be highlighted. A too
large threshold setting will detect only a
large movement as a stroke, a too small
setting may detect too many strokes. You
must test and adjust this according to your
swimming style. By pressing the +/UP or -/
DOWN buttons the value can be selected
from 2cm/1in to 40cm/16in. A short press
of the SEL/ESC button saves the setting.
Pressing the SEL/ESC button will take
you back to the previous submenu where
you can toggle down to the stroke length
settings. These values can be set from
0.5m/2ft to 5.0m/16ft by pressing the +/UP
or -/DOWN buttons. Conrm your settings
by pressing the SEL/ESC button.
To convert each stroke to a distance, the
A2 needs an average length of a stroke.
This is similar to a pedometer which uses
a step length to convert the distance. You
can calibrate this in a swimming pool where
you know the length and can use the A2
stroke count to calculate the correct length.
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3.1.3 Sound settings
SOUND
BUZZER
BUTTON
DIVE
RETURN
SEL
UP
DOWN
ESC
UP
UP
UP
DOWN
DOWN
DOWN
ESC
Next on the Settings menu listing is
Sound. Press the SEL/ESC button to enter.
3.1.3.1 Buzzer
When delivered with factory settings the
A2’s buzzer is active. You can set the A2
to a stealth mode in the Buzzer submenu
which deactivates all sounds. However,
switching off all alarm sounds requires
the safety code 313 to prevent accidental
deactivation.
3.1.3.2 Button beeps
In this submenu the general button
feedback beeps can be enabled or disabled
by pressing the +/UP or -/DOWN buttons
followed by SEL/ESC to save the setting.
3.1.3.3 Dive warnings
In this submenu the warnings in dive mode
can be enabled or disabled by pressing the
+/UP or -/DOWN buttons followed by SEL/
ESC to save the setting.
English
Setting the “BUZZER OFF” will disable all
audible dive mode alarms and warnings. This
could potentially be dangerous.
A2 USER MANUAL
WARNING
NOTE: Dive alarms are still active
F
even if you switch the dive warnings
off. Dive alarms are deactivated only
when the buzzer is switched off as
described in chapter 3.1.3.1 Buzzer.
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3.1.4 Checking the battery status
DIVE
MODE
SCUBA
APNEA
RETURN
UP
DOWN
SEL
ESC
ESC
DOWN
DOWN
DOWN
UP
UP
UP
WARNING
DOWN
UP
MODE
APNEA
SCUBA
GAUGE
UP
DOWN
SEL
ESC
DOWN
ESC
DOWN
UP
UP
When the menu Battery is selected, the A2
shows the last measured battery level.
If you press the SEL/ESC button while in
this menu, a new measurement will be
made. This might take a few seconds. The
A2 will display a “please wait” message
until the revised battery status is available.
3.2 Dive settings on surface
From the main menu enter the Dive menu
by pressing the SEL/ESC button.
3.2.1 Dive mode selection
The Mode menu allows you to select your
preferred dive mode: Apnea, Scuba or
Gauge mode.
32
NOTE: The GAUGE and APNEA
F
modes do not track tissue saturation
so there is a locking interval before
it is possible to change to SCUBA
mode. In GAUGE mode the locking
interval is 48h after the last dive in
GAUGE mode. In APNEA mode there
is a 12h locking interval with shallower
than 5m/16ft dives, and a 24h locking
interval with deeper than 5m/16ft
dives.
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3.2.2 Scuba mode settings
SCUBA
WATER
MB-LEVEL
CCR
SIDE MOUNT
PMG
TRIMIX
RETURN
SEL
ESC
ESC
UP
DOWN
UP
DOWN
UP
DOWN
UP
DOWN
UP
DOWN
UP
DOWN
UP
DOWN
DISPLAY
UP
DOWN
A set of SCUBA related selections are
grouped in this menu.
By pressing the SEL/ESC button you can
scroll through the following submenus:
3.2.2.1 Water type selection
The A2 determines depth by measuring
pressure using water density as a constant.
A 10m/33ft depth in salt water corresponds
approximately to 10.3m/34ft in fresh water.
By pressing the +/UP or -/DOWN buttons
you may select either salt or fresh water.
The selection is conrmed by pressing the
SEL/ESC button.
NOTE: This setting will adjust the
F
depth on all modes: SCUBA, GAUGE
and APNEA.
English
A2 USER MANUAL
3.2.2.2 Microbubble level selection
By pressing the SEL/ESC button in
this menu the Microbubble level will be
highlighted. By pressing the +/UP or -/
DOWN buttons you may select your
personal setting from L0 up to L9.
L9 is the most conservative setting. The
selection is conrmed by pressing the SEL/
ESC button.
NOTE: More about diving with
F
microbubble levels can be found in
section 4.7 Diving with MB-levels.
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3.2.2.3 Dive display type
In this menu the display type while diving
in SCUBA and GAUGE modes can be
selected. You will nd a more detailed
description about diving with light and
classic displays in chapter 4.1.2.1 SCUBA
mode display selection and 4.1.2.2
GAUGE mode display selection.
For example, the % value of the O2
correction increases the nominally set
value for the CNS% clock value and
ppO
2
N2 correction decreases the nominally set
ppO2 value for the inert gas absorption
(algorithm).
3.2.2.4 Enabling CCR mode
In order to enable the CCR mode, enter
the main menu and go to Dive -> Scuba ->
CCR and select “ON” by pressing the SEL/
ESC button.
Enabling CCR changes the default open
circuit gas content settings to setpoint
settings.
Since the CCR dive unit is responsible for
the setpoint accuracy and the A2 is using
that accurate number, you can select
some conservatism with an O
and inert
2
gas correction (it is shown as N2 but also
inuences He when the TMx option is
enabled).
You can set the conservatism for both in
the range from 0 up to 10% as shown in
following screens.
NOTE: Activating sidemount or CCR
F
diving modes will automatically enable
the PMG mode. Refer to chapter 4.13 Diving with CCR mode to learn more
about how the display is congured in
this mode.
3.2.2.5 Enabling Sidemount mode
In order to enable the sidemount mode,
enter the main menu and go to Dive -> Scuba -> Sidemnt and select “ON” by
pressing the SEL/ESC button.
The pressure step denes the pressure
difference between tanks when the A2
alerts you to switch from the lower to the
higher supply side. You can choose a step
between 10 and 50 bars or follow the rule
of thirds.
34
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F
APNEA
TOTAL
EXERCISE
SIF
DEPTH
DIVE
INCREMENTAL
DIVE INTERVAL
SURFACE
INTERVAL
SPEED
RETURN
SEL
ESC
DOWN
UP
UP
UP
UP
UP
UP
UP
UP
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
ESC
LOW HR
UP
DOWN
3.2.2.6 Enabling PMG mode
In order to enable the PMG mode, enter the
main menu and go to Dive -> Scuba -> PMG and select “ON” by pressing the SEL/
ESC button.
Predictive Multigas (PMG) mode enables
the use of multiple tanks from 2 to 8. See
chapter 4.15 Diving with multiple gas mixtures to learn more about how to use
this feature.
F
A2 USER MANUAL
3.2.2.7 Enabling Trimix mode
In order to enable the Trimix mode, enter
the main menu and go to Dive -> Scuba
-> Trimix and select “ON” by pressing the
SEL/ESC button.
When Trimix is on, the gas content
presentation follows the standard O2/He.
Also, the AMD (Absolute Minimum Depth)
for each gas is shown. See chapter 4.16 Diving with Trimix mode to learn more
about this feature.
NOTE: Activating sidemount or CCR
diving modes will automatically enable
the PMG mode. Refer to chapter 4.14 Diving with Sidemount mode to
learn more about how the display is
congured in this mode.
NOTE: PMG must be enabled for
sidemount and CCR diving modes.
3.2.3 Apnea mode settings
Apnea diving-related selections are
grouped in this menu.
By pressing the SEL/ESC button the
following submenus can be accessed:
English
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3.2.3.1 Total Apnea exercise depth
To provide a scale of total pressure changes
during an Apnea dive session, the A2
includes a total depth counter. By pressing
the +/UP or -/DOWN buttons you can set
the total depth counter from 100m/300ft
to 1000m/3301ft, and save the setting
by pressing the SEL/ESC button. When
your depth total has been reached the A2
noties you at the surface with an audible
tone and a blinking “no dive” symbol to let
you know it’s time to end the session and
take a break.
3.2.3.2 Surface interval factor
Apnea diving organizations provide various
recommendations regarding surface
intervals between dives based on dive
times or depths. The A2 integrates a
surface interval counter which employs
simple multiplication for determining the
surface interval in seconds. The A2 uses the
following formula to make this calculation:
Surface interval before the next dive =
pressure (depth) * square root of dive time
* SIF.
As a reference, a few values are listed in the
following table:
DIVE
DEPTH
m
10304063253
10306077309
206060116464
309080178716
4012090237949
NOTE: The actual depth and time
F
are calculated during the ascent and
descent. This is not presented in the
table above.
DIVE
TIME
ft
seconds
SURFACE
INTERVAL
seconds
(SIF = 5)
seconds
(SIF = 20)
36
The SIF can be selected from 5 to 20 or
disabled with the OFF setting by pressing
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Page 37
the +/UP or -/DOWN buttons and then the
SEL/ESC button to save.
In the upper left section of the screen the
depth of the rst alarm is displayed.
3.2.3.3 Dual depth alarm
In initial factory settings the dual dive depth
alarm is switched off.
Once you have enabled this feature by
selecting “AUDIBLE” in this menu, the rst
depth selection will be shown. By pressing
the SEL/ESC button the A2 will display the
second depth selection .
NOTE: The rst alarm is short
F
sequence to get your attention, while
the second alarm is continuous. By
setting the rst alarm deeper than
the second, it will be masked by the
continuous alarm and you may not be
able to hear it.
3.2.3.4 Dive depth incremental alarm
In initial factory settings the dive depth
incremental alarm is switched off.
You may select the alarm value from 5 to
100m (20 to 330ft) in 1m/5ft increments,
and the direction can be selected as UP/
DOWN/BOTH. Press the +/UP or -/DOWN
buttons to select direction, then the SEL/
ESC button, then the +/UP or -/DOWN
buttons again to set the depth, followed by
a nal press of the SEL/ESC button to save
the setting.
English
Both depth alarms can be set from 5 to 100
meters (20 to 330 feet) in 1m/5ft increments
by pressing the +/UP or -/DOWN buttons.
By pressing the SEL/ESC button the rst
value is conrmed and the second depth
can be adjusted.
The value of the second alarm can be set
the same way as that of the rst alarm.
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3.2.3.5 Dive time interval alarm
By pressing the SEL/ESC button the
function will be highlighted and you may
enable or disable the dive time interval
alarm by choosing AUDIBLE or OFF by
pressing the +/UP or -/DOWN buttons.
By selecting AUDIBLE and then pressing
the SEL/ESC button the time value will
be highlighted, and by pressing the +/UP
or -/DOWN buttons you can select the
interval from 15 seconds up to 10 minutes
in 15 second increments. By pressing the
SEL/ESC button again the settings will be
conrmed.
3.2.3.6 Surface interval alarm
By pressing the SEL/ESC button the
function will be highlighted and you may
enable or disable the surface interval alarm
by choosing AUDIBLE or OFF by pressing
the +/UP or -/DOWN buttons. By selecting
AUDIBLE and then pressing the SEL/ESC
button the time value will be highlighted,
and by pressing the +/UP or -/DOWN
buttons you can select the interval from 15
seconds up to 10 minutes in 15 second
increments. By pressing the SEL/ESC
button again the settings will be conrmed.
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3.2.3.7 Low heart rate alarm
WARNING
DIVE TIME
DEPTH
MOD
RETURN
UP
DOWN
SEL
ESC
ESC
DOWN
DOWN
DOWN
UP
UP
UP
LIGHT
DOWN
UP
The A2 can trigger an alarm if your heart
rate drops below a set level. The alarm
can be set between 25 and 100 beats per
minute.
By pressing the SEL/ESC button the
function will be highlighted and you may
enable or disable the low heart rate alarm
by choosing AUDIBLE or OFF by pressing
the +/UP or -/DOWN buttons. By selecting
AUDIBLE and then pressing the SEL/ESC
button the value will be highlighted and by
pressing the +/UP or -/DOWN buttons you
can select the interval from 25 to 100. By
pressing SEL/ESC again the settings will be
conrmed.
English
3.2.4 Warning settings
There are three warnings which can be
enabled and edited directly in the A2. The
rest of the warnings can only be enabled
/ disabled via SCUBAPRO LogTRAK
program. To learn more about the warnings
see chapter 4.4 Alarms and warnings
during diving.
3.2.3.8 Ascent speed alarm
By pressing the SEL/ESC button the
function will be highlighted and you may
enable or disable the ascent speed alarm
by choosing AUDIBLE or OFF by pressing
the +/UP or -/DOWN buttons. By selecting
AUDIBLE and then pressing the SEL/ESC
button the value will be highlighted, and
by pressing the +/UP or -/DOWN buttons
you can select the interval from 0.1 to
5.0 meters/second (1 to 15 feet/second)
in 0.1m/sec or 1ft/sec increments. By
pressing the SEL/ESC button again the
settings will be conrmed.
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3.2.4.1 Setting the dive time warning
In initial factory settings the dive time
warning is switched off. When you select
dive time and switch the warning on,
the value can be adjusted from 5 to
195 minutes in 5-minute increments by
pressing the +/UP or -/DOWN buttons. The
selection is conrmed by pressing the SEL/
ESC button.
3.2.4.2 Setting the dive depth
warning
In initial factory settings the dive depth
warning is switched off. When you select
dive depth and switch the warning on, the
value can be adjusted from 5 to 100m (20
to 330ft) in 1m/5ft increments by pressing
the +/UP or -/DOWN buttons. The
selection is conrmed by pressing the SEL/
ESC button.
3.2.4.3 Setting the MOD alarm
In initial factory settings the MOD alarm
is enabled. If the alarm is disabled, this
requires the safety code 313 from the user
to prevent accidental switching off.
MOD alarm uses the maximum ppO2 value
which is given at the gas settings and the
default value is 1.4bar.
WARNING
Diving at oxygen partial pressures higher than
1.6bar is extremely dangerous and could lead
to serious injury or death
3.2.4.4 Setting the visual warning
signal
In this menu you can enable or disable
the A2’s function of warning you with the
lighting up of the display backlight in case
a warning or alarm is triggered. This is
an additional feature to the A2’s audible
warning signals, which can help make the
diver aware of the presence of a warning in
case the audible sequence would not be
heard.
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GAS
GAS MIX
PAIRING
O2 RESET
SEL
ESC
DOWN
UP
UP
UP
DOWN
DOWN
FULL GAS
UP
DOWN
HALF GAS
UP
DOWN
RESERVE
UP
DOWN
RETURN
UP
DOWN
3.3 Gas settings
In this section gas related settings are
described. From the main menu toggle
down to the Gas menu and press the SEL/
ESC button to enter.
3.3.1 Setting gas oxygen content
For normal one-tank diving you can select a
gas mix from 21% oxygen (Air) up to 100%
oxygen. The ppO
the MOD limit you intend to use for this gas.
max value is required for
2
The factory setting is 1.40bar.
By pressing the SEL/ESC button in the
Gas mix submenu the oxygen content of
the gas will be highlighted. By pressing the
+/UP or -/DOWN buttons you may set the
value from 21% up to 100%.
NOTE: Setting the gas mix will be
F
disabled if the selected dive mode is
Apnea or Gauge.
Once the oxygen content of a tank is
conrmed by pressing SEL/ESC, the
selection changes to ppO
limit value. By
2
pressing the +/UP or -/DOWN buttons
you may select a value from 1.00bar up to
1.60bar. A press of the SEL/ESC button will
save the selection.
English
Here you can change the gas content of
the tanks that you are using as well as
the partial pressure limit of the gas. The
Maximum Operating Depth (MOD) limit
will be shown for the values that you have
selected. To learn more about diving with
Nitrox and MOD, see chapter 4.10 Diving with Nitrox.
A2 USER MANUAL
NOTE: If you cancel the ppO2 setting
F
by a press-and-hold of the SEL/ESC
button, the oxygen content selection
will also be canceled.
WARNING
Diving with a ppO2 higher than 1.6bar is
dangerous and may lead to unconsciousness,
drowning and fatal injury.
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NOTE: ppO2 is xed to 1.60bar when
F
the selected oxygen content is 80% or
higher.
3.3.1.1 Predictive multi gas (PMG)
If PMG is enabled, up to 8 tanks can be
preset and paired and the O
appear as follows:
After selecting the tank (T1 in the picture
above) and pressing the SEL/SEC button,
the oxygen fraction can be edited. After
conrming the oxygen fraction, you need
to set the maximum ppO2 value in the
following screen. After conrming this with
the SEL/ESC button, the tank is ready to
be used.
T1 is always the default gas at the start of
the dive. Other tank values (T2 to T8) can
be congured the same way as Tank 1.
settings will
2
3.3.1.2 Trimix
When trimix mode is enabled the O
settings will appear as follows:
The tank selection works the same way as
with PMG (T1-T8). First the selected tank’s
oxygen content has to be set, followed by
the helium fraction.
NOTE: To ensure an adequate supply
F
of oxygen to the body, the gas used at
the beginning of the dive must contain
enough oxygen. Since the dive always
starts with tank T1, the minimum O2
setting for tank T1 is 18%. For tanks
T2 to T8 the minimum oxygen fraction
is 8%.
2
42
NOTE: You can set a different ppO2
F
value for decompression gases than
for bottom gases.
NOTE: See chapter 3.2.2.6 Enabling
F
PMG mode to learn how to enable
this feature. For further information
about diving with PMG mode, please
refer to chapter 4.15 Diving with multiple gas mixtures.
After the oxygen and helium contents are
conrmed by pressing SEL/ESC, you have
to set the maximum and minimum ppO
limits. The MOD (Maximum Operating
Depth) and the AMD (Absolute Minimum
Depth) are shown in the bottom row of
these screens.
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WARNING
The AMD depends on the ppO2min value. If the
alarm depth is shallower than 0.8m/3ft which
is the dive start depth for the A2, the alarm
will not activate before a 0.8m/3ft depth is
reached! This situation is dangerous and may
lead to death by drowning.
to 0.95bar. By pressing the SEL button the
given values are conrmed.
English
WARNING
Engaging in heavy work while at the surface or
at shallow depths while breathing less than a
21% oxygen (hypoxic mix) fraction may cause
a loss of consciousness and lead to drowning.
NOTE: See chapter 3.2.2.7 Enabling
F
Trimix mode to learn how to enable
this feature. For further information
about diving with TMx mode, please
refer to chapter 4.16 Diving with
Trimix mode.
3.3.1.3 CCR
If the CCR mode is enabled the diluent tank
will appear as follows:
By pressing the SEL/ESC button in this
screen the oxygen concentration of the
diluent tank can be set in a range from 21%
to 40%:
The bottom setpoint (SP2) has a range
from 1.0bar up to 1.4bar ppO2 and this
is switched normally active on the way to
the bottom or when the bottom depth is
reached. SP2 is dedicated to the oxygen
tank and the setting procedure is as with
SP1.
NOTE: See chapter 3.2.2.4 Enabling
F
CCR mode to learn how to enable
this feature. For further information
about diving with CCR mode, please
refer to chapter 4.13 Diving with
CCR mode.
By pressing the SEL/ESC button, the tank
content is conrmed and the dive start
setpoint (SP1) ppO2 will be highlighted.
By pressing the +/UP or -/DOWN buttons
you may select the value from 0.3bar up
A2 USER MANUAL
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3.3.2 Mounting and pairing the
high pressure transmitter
The A2 can receive tank pressure
information from multiple Smart series high
pressure transmitters. Each transmitter
needs to be mounted on a high pressure
port of a rst stage regulator. To mount the
transmitter, rst remove the high pressure
port plug from the rst stage regulator, then
screw the transmitter in place.
NOTE: Use an appropriate wrench to
F
tighten the transmitter. Take care to
not overtighten.
The Smart transmitter communicates via
radio frequency with the A2. For optimal
transmission performance, we recommend
positioning the transmitter as described in
the pictures below.
44
Transmitter position for the left hand.
A2 USER MANUAL
Page 45
Transmitter position for the right hand.
In order for the A2 to display the pressure
signal from a Smart transmitter, a coded,
interference-free line of communication
must rst be established. This step needs
to be performed only once for each
transmitter.
Proceed as follows:
• Mount the first stage regulator with the
Smart transmitter on a full tank.
• Set the A2 to pairing mode (Gas -> Pairing) and press SEL/ESC. The
display shows “PAIR TANK”. Place the
A2 near the transmitter.
• Open the tank valve.
Upon pressurization, the Smart transmitter
will send a pairing sequence to the A2.
When the A2 receives this information, the
display changes to show a listing of tank
designations. (T1, T2, etc.).
Tank T1 is always the main tank you start
your dive with. Other tanks are used when
diving with more than one gas mixture
described in chapter 4.15 Diving with
multiple gas mixtures.
Use the +/UP or -/DOWN buttons to select
the tank that you want to assign to the
transmitter, then conrm it with a press of
the SEL/ESC button. The current pressure
of the paired tank will appear on the bottom
row in either BAR or PSI.
If the tank has not been paired, the A2 will
show “nOP” instead of a pressure value.
If T1 has been paired but the A2 is not
receiving any signal, it will show - - - instead
of a pressure value.
NOTE: The transmitter must have
F
been unpressurized for at least 40
seconds prior to performing the
pairing operation; otherwise it will
not transmit the pairing sequence.
A transmitter can only be paired to
one tank designation. If you pair the
same transmitter to a second tank
designation, the rst one will be
erased. However, you can pair more
than one A2 (or other compatible
SCUBAPRO dive computers) to the
same transmitter.
English
A2 USER MANUAL
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NOTE: The Smart transmitter has
F
a range of approximately 1.5m/5ft.
• To maximize the life of the battery,
the transmitter operates at a low
update rate when there is no pressure
change for more than 40 seconds. The
transmitter also turns itself off when
the pressure is 14bar/200psi or less.
• If a transmitter battery is weak,
the A2 will alert you with a screen
message displaying the tank assigned
to that transmitter as shown on the
screen below (T1 batt).
See chapter 7.5 Replacing the battery
in the high pressure transmitter
for information on how to replace the
transmitter’s battery.
3.3.3 Nitrox reset time
If you are generally diving with air and want
to return to this setting after the occasional
nitrox dive, you can preset a default time
when your A2 will set back to air.
By pressing the SEL/ESC button the
time shown on the bottom row will be
highlighted. The time can be selected from
1 hour up to 48 hours by pressing the +/UP
or -/DOWN buttons. The nitrox reset time
can be disabled by pressing the +/UP or -/
DOWN buttons until -- h is shown on the
display. A press of the SEL/ESC button will
save the setting.
3.3.4 Full gas
The analog bar graph on the right side
of the display indicates the selected tank
pressure when this is enabled (ON). To
scale the graph you need to select the
maximum (full) tank pressure. This can be
set from 100 to 300 bar.
46
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3.3.5 Setting the half tank warning
By pressing the SEL/ESC button the status
ON/OFF will be highlighted. You can enable
the half gas warning by selecting “ON” and
disable it by selecting “OFF”. By activating
the half gas warning the pressure value will
be highlighted and you may set a value
from 50 to 200bar in 5-bar increments
(749..2999psi in 50-psi increments) by
pressing the +/UP or -/DOWN buttons. By
pressing SEL/ESC you conrm the settings.
3.4 Planning a dive
You can plan your next dive based on your
body’s nitrogen saturation. The planner is
also using the following information:
1. Selected oxygen concentration.
2. Selected water type.
3. Selected microbubble level.
4. Water temperature of the most recent
dive.
5. Altitude range.
6. Status of saturation at the time when
the planner is activated.
7. Observance of the prescribed ascent
rates.
To set up a new dive plan, scroll to the
planner menu and press SEL/ESC.
English
3.3.6 Setting the tank reserve
By pressing the SEL/ESC button the
pressure value will be highlighted and
you may set a value from 20 to 120bar
in 5-bar increments (299..1749psi in 50psi increments) by pressing the +/UP or
-/DOWN buttons. Pressing the SEL/ESC
button will conrm the settings.
F
A2 USER MANUAL
alarm
NOTE: Reaching the tank reserve
pressure triggers an alarm. In the RBT
calculation the tank reserve pressure
is dening the complete used tank.
The reserve pressure should still be in
the tank when surfacing
3.4.1 No-stop plan
If you have completed a dive but plan to
make another during the desaturation
phase, you must start the planner by
adding the time you would otherwise be
on the surface. The time can be added in
15-minute increments.
The prohibited altitude class is shown after
the current elevation at the bottom line. For
more information on altitude diving with
the A2, see chapter: 4.9 Altitude diving.
In case the A2 is displaying the no-dive
warning, the duration of the warning itself
is displayed as a recommended surface
interval for planning purposes (rounded up
to the nearest 15-minute increment).
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When the surface interval is given, or if
you have no remaining desaturation left,
the planner can show depth in 3m/10ft
increments and scrolled by pressing +/UP
or -/DOWN. The no-decompression dive
time is shown for that depth. The current
gas mix is shown on the bottom row.
CNS% value replaces the gas mix on the
bottom left of the screen when 1% would
be reached for that depth with maximum
no-stop time.
NOTE: The minimum depth for dive
F
planning is 9m/30ft. The planner
allows only depths in line with
maximum ppO2. The oxygen content
and maximum ppO2 settings are given
in the menu GAS.
If the MOD is shallower than 9m/30ft,
planning is not allowed and the A2 will
show “MOD: LOW”
3.4.2 Decompression plan
After conrming the planned dive depth
with the SEL/ESC button, the planned dive
time can be set by pressing the +/UP or -/
DOWN buttons.
In the below image the planned dive time is
minimum 17 minutes.
The start point (17 minutes) is the “no
decompression” time. The deepest
decompression or MB-level stop is also
shown as well as the Total Ascent Time.
NOTE: When the A2 is in GAUGE or
F
APNEA modes, the Planner is disabled
and this is indicated by a display like
the following:
3.5 Reading the logbook
You can review your dive and step counter
statistics by pressing the SEL/ESC button
when in the Logbook menu.
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3.5.1 Dive statistics
Enter the Dive submenu from the Logbook
menu to view your dive statistics.
On the display below, the A2 has 11 dives
and total of 6 hours of diving in the Logbook,
with the deepest dive at 57.0 meters and a
longest dive time of 80 minutes.
By pressing the SEL/ESC button you will
enter the repository of the logs where you
can scroll through your dives with the +/
UP or -/DOWN buttons. The below display
shows the following information: Dive
number, dive mode, dive start time and
date.
English
By pressing the +/UP button on the above
screen the following information will appear
as in the screen below:
Counted repetitive dive (rep 1 is the rst
dive), start and nish time, microbubble
level (L5) and the altitude class (C0) of the
dive. By pressing +/UP in the above screen
the tank information of the selected dive will
be displayed:
By pressing the SEL/ESC button on
the above screen the A2 will display the
graphical prole of the dive. This screen
shows the following information: Maximum
depth, total duration of the dive, minimum
temperature of the water, active heart rate
function and the tank pressure.
A2 USER MANUAL
NOTE: The capacity of the A2’s
F
logbook is around 50 hours with a
4-second sampling rate.
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3.5.2 Step counter statistics
Enter the Stepctr (Stepcounter) submenu
from the Logbook menu to view your step
counter statistics.
With the +/UP and -/DOWN buttons you
can scroll through your daily, weekly and
monthly step counter statistics.
4. DIVING WITH THE A2
The A2 is a full-featured diving computer
capable of multi-gas Nitrox decompression
calculations, CCR mode, ascent rate
calculations and warnings. During a
dive the A2 displays information such as
depth, dive time, decompression status,
water temperature, tank information, true
remaining bottom time and much more.
On the surface after a dive, remaining
desaturation time, no-y time, surface
interval and prohibited altitude classes are
shown in addition to the watch functions.
Note that the A2 can be set to three dive
modes: SCUBA, APNEA and GAUGE.
Due to the operational differences between
modes, the buttons will have different
functions depending on which mode you
are using.
The functions of the buttons during diving
are summarized in the table below:
Press = backlight
“LIGHT”
“SEL/ESC”
“+/UP”
“-/DOWN”
Press-and-hold = launch
compass
Press-and-hold in Apnea
mode when in “surface
interval” display = end Apnea
exercise
Press = set bookmark
Press = scroll through
alternative dive displays
Press-and-hold in GAUGE
mode when average depth
on display = reset average
depth counter
Press-and-hold in GAUGE
and SCUBA mode when
timer on display = stop/
restart the timer
Press = scroll through
alternative dive displays
Press-and-hold in Apnea
mode when in “surface
interval” display = end Apnea
exercise
Press-and-hold in GAUGE
and SCUBA mode when
timer on display and stopped
= reset timer to zero
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4.1 Display information
Upon immersion, the A2 will automatically
start to monitor the dive regardless of
what state it was in prior to the immersion.
Details on the information displayed can be
found in the next sections.
Dive time: the dive time is displayed in
seconds in APNEA mode and in minutes
in SCUBA and GAUGE modes. If during
the dive you ascend to the surface, the
time spent on the surface will only be
counted to the dive time if you descend
again below 0.8m/3ft within 5 minutes.
This allows for brief periods of orientation.
While on the surface, the time will not
show as progressing but it is running in the
background. As soon as you submerge,
the time will resume, including the time
spent on the surface. If you spend more
than 5 minutes at a depth shallower than
0.8m/3ft, the dive will be considered
ended, it is stored in the logbook and a
subsequent immersion would cause the
dive time to start again from zero.
Maximum displayed time is 999 minutes.
For dives longer than that, the dive time
starts again from 0 minutes.
Depth: the depth is displayed in 0.1m
resolution when the metric system is
set. When depth is displayed in feet, the
resolution is always 1 foot. Maximum
operating depth is 120m/394ft.
No-stop time: calculated in real time and
updated every 4 seconds. The maximum
displayed no-stop time is 199 minutes.
4.1.1 Dive ready mode
A press-and-hold of the -/DOWN button
in the main time and date display will give
you access to the dive ready mode which
shows you your current dive settings.
Information like dive mode, current MBlevel, water type selection, MOD, gas
oxygen content and tank pressure will be
displayed as follows:
After a dive there are further displays which
can be shown by pressing the -/DOWN
button. These displays can identify for
example the no-dive time (10h), no-y time
(2h), surface interval (0:06), repetitive dive
number (1) and current & prohibited altitude
classes (03).
By a further press of the -/DOWN button
the no-dive time (10h), no-y time (2h), and
remaining desaturation time (13:50) will be
shown.
English
During all dives, perform a safety stop
between 3 and 5 meters/10 and 15 feet for 3
to 5 minutes, even if no decompression stops
are required.
The following chapter describes the
SCUBA mode diving functions, if you are
using GAUGE or APNEA dive modes, these
are further described in chapters 4.11
Diving in GAUGE mode and 4.12 Diving
in APNEA mode.
A2 USER MANUAL
WARNING
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4.1.2 Display conguration during
the dive
Throughout the dive, the A2 displays
depth and dive time always at the top
row of the screen. Gas mix and the water
temperature are shown at the bottom
row. The information in the middle of the
screen changes and it is also selectable by
pressing the +/UP or -/DOWN buttons.
4.1.2.1.1 Light version
No-Stop Time,
which is the
time that can be
spent at current
depth before
decompression
stops are required.
4.1.2.1 SCUBA mode display
In SCUBA mode you can choose from
two display versions while diving: Light or
Classic. The following screens illustrate
the information in the middle of the screen
which can be selected as shown in the
sections below.
F
selection
NOTE: The default information in the
middle of the screen at the beginning
of the dive is the No-Stop Time. If
you select another information in
the middle of the screen, there is no
timeout to the default except when
decompression limit is reached.
Decompression time and depth
are appearing in the middle of the
screen after 3 minutes from any other
selected screen.
Current depth is
shown in feet or full
meters without a
comma. This is the
larger duplicate of
the top row depth.
Elapsed Dive Time,
this is a larger
duplicate of the top
row dive time.
Tank pressure
Remaining Bottom
Time
52
Gas Oxygen
Content, this is a
larger duplicate of
the bottom row
O2% value.
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4.1.2.1.2 Classic version
No-Stop Time
Remaining Bottom
Time
Current MB-level
Heart rate
Current time of the
day
Water temperature
Skin temperature
Maximum depth
reached during
current dive
Decompression
stop
4.1.2.2 GAUGE mode display
selection
In GAUGE mode you can choose from
two display versions while diving: Light or
Classic. The following screens illustrate
the information in the middle of the screen
which can be selected as shown in the
sections below.
English
A2 USER MANUAL
Timer
NOTE: When the A2 is set to GAUGE
F
mode, it will only monitor depth, time,
and temperature, and it will not carry
out any decompression calculations.
Due to this there are fewer alternative
displays to scroll through.
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4.1.2.2.1 Light version
4.1.2.2.2 Classic version
Timer
Current depth
Elapsed dive time
Average depth
Timer
Average depth
Maximum depth
reached during the
current dive
Current time of the
day
54
Tank pressure
NOTE: The average depth can be
F
reset by a press-and-hold of the +/UP
button when it is active on the screen.
Heart rate
Skin temperature
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NOTE: In Gauge and Scuba mode
F
when the timer is displayed, it can be
stopped by a press-and-hold of the
+/UP button. A repeated press-andhold of the +/UP button will restart the
timer. When the timer is stopped, it
can be reset to zero by pressing and
holding the -/DOWN button.
4.1.2.3 APNEA mode
If the Apnea mode is triggered manually
by selecting Apnea in the Sport menu,
the surface interval starts counting in the
middle of the display without previous dive
information (depth is - - - at the top and
repetitive dive count is 0 at the bottom row)
as in the screen below:
However, after an immersion the surface
screen shows the last max depth, surface
interval, water temperature and amount of
repetitive dives during the APNEA session.
Heart rate
Total time of current
Apnea dive session
After the second immersion, by scrolling
through the Apnea dive displays with the
+/UP or -/DOWN buttons, the following
additional information will be displayed:
Duration of last
immersion
English
From the surface interval display by
pressing the +/UP button you can scroll
through the following displays:
A2 USER MANUAL
Skin temperature
Maximum depth
reached during last
immersion
During an immersion in Apnea mode these
four screens show the current dive depth
and duration as well as the current heart
rate and skin temperature values and they
can be scrolled through by pressing the +/
UP or -/DOWN buttons.
NOTE: The dive depth displayed in
F
large size in the middle part of the
screen is shown with no decimal
values rounded up or down, but
the actual depth is always precisely
saved and shown in the logbook with
0.1m/1ft accuracy.
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4.2 Safety stop timer
If a minimum depth of 10m/30ft is reached
during the dive, at a depth of 5m/15ft the
safety stop timer will automatically start
a 3-minute countdown. If you go below
6.5m/20ft, the timer will disappear and the
no-stop time will be shown again. Upon
returning to 5m/15ft, the timer will start
again automatically.
4.3 Activating the backlight
To activate the backlight, press the
LIGHT button. For setting the duration
of the backlight refer to chapter 3.1.1.2
Backlight.
NOTE: The backlight is not available
F
when the CHANGE BATTERY warning
appears.
by pressing the SEL/ESC button which
changes the alarm display back to the
normal dive display. However, if the
warning condition continues, the warning
can be recalled by scrolling with the +/
UP or -/DOWN buttons. Alarms can also
be conrmed by pressing the SEL/ESC
button, but they remain on the alternate
display which can be scrolled through with
the +/UP or -/DOWN buttons.
WARNING
When in Gauge mode, all warnings and all
alarms are OFF except for the low battery, tank
reserve, half tank, max depth, max dive time
and pressure signal alarms.
When the A2’s buzzer is disabled all audible
alarms and warnings are muted but will still
appear on the display if triggered.
4.4.1 Maximum depth warning
If you have enabled the maximum depth
warning, the below display will be shown
when the selected depth is reached.
Refer to chapter 3.2.4.2 Setting the dive depth warning to learn how to enable this
warning.
56
4.4 Alarms and warnings
during diving
The A2 can alert you to potentially
dangerous situations via warnings and
alarms. You can modify the warning and
alarm settings in the menus or via the
LogTRAK interface.
General warnings and alarms are shown in
inverted text (white with black background)
in the middle of the display. Additionally,
audible signals are available when the
sound function is enabled. You can also
set a visual warning function, where the
A2’s display backlighting would indicate
if an alarm or warning was triggered. If
this feature is enabled, the backlight will
light up for the duration of the respective
warning. Refer to chapter 3.2.4.4 Setting the visual warning signal to learn how
to enable this feature. Warnings are shown
for 12 seconds or they can be conrmed
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4.4.2 MOD (ppO2max) alarm
If you exceed the maximum partial pressure
of the selected gas, the following alarm is
shown: MOD + DEPTH. The alarm remains
active until you ascend to a depth where
the ppO
is within safe limits.
2
4.4.4 Dive time warning
If you have enabled the dive time warning,
this will be shown by a screen like the
below when the selected time is reached.
Refer to chapter 3.2.4.1 Setting the dive time warning to learn how to enable this
warning.
English
WARNING
The MOD should not be exceeded. Disregarding
the alarm can lead to oxygen poisoning.
Exceeding a ppO2 of 1.6bar can lead to sudden
convulsions resulting in serious injury or fatal
issue.
4.4.3 AMD (ppO
min) alarm
2
When diving with multiple gas mixtures
at shallower depths than the AMD for the
current gas mix, the absolute minimum
depth alarm will be triggered. For more
information about the AMD refer to chapter
4.16.1 Absolute Minimum Depth and
Maximum Operating Depth.
WARNING
The AMD depends on the ppO2min value. If the
alarm depth is shallower than 0.8m/3ft which
is the dive start depth for the A2, the alarm
will not activate before a 0.8m/3ft depth is
reached! This situation is dangerous and may
lead to death by drowning.
4.4.5 Turning time
When dive time warning is activated the A2
will alert you when it’s time to turn around
and start ascending to the surface.
4.4.6 No-stop time = 2 minute
warning
If you wish to avoid unintentionally
performing a decompression dive, the A2
can activate a warning when the no-stop
time reaches 2 minutes. This applies to
both L0 no-stop and MB no-stop time
(see chapter 4.7 Diving with MB-levels
for more information on MB-level diving). It
gives you the opportunity to start ascending
before incurring a decompression stop or a
level stop obligation.
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4.4.7 No-stop time warning
The A2 can activate a warning when
the rst mandatory decompression stop
appears. This alerts you to the fact that a
direct ascent to the surface is no longer
possible.
4.4.8 CNS O2 warning (over 75%)
The A2 tracks your oxygen uptake via the
CNS O
clock. If the calculated value of
2
CNS O
reaches 75%, the A2 will emit a
2
sequence of audible beeps for 12 seconds
and the following display will be shown.
4.4.9 CNS O2 alarm (100%)
The A2 tracks your oxygen uptake via the
CNS O
clock. If the calculated value of
2
CNS O2 reaches 100%, the A2 will emit a
sequence of audible beeps for 12 seconds
and the CNS 100% alarm will be shown.
4.4.10 L0 no-stop time = 2 minute
warning
When diving with an MB-level higher than
L0, the underlying L0 information is not
directly visible on the display (though it is
accessible as alternate information). You
can choose to have your A2 warn you when
the underlying L0 no-stop time reaches 2
minutes while diving with an active MBlevel higher than L0.
4.4.11 Entering decompression
warning
The A2 can activate a warning when
the rst mandatory decompression stop
appears. This alerts the diver to the fact
that a direct ascent to the surface is no
longer possible. This warning applies to
dives with the computer set to L0-L9.
58
WARNING
When the CNS O2 reaches 100% there is
danger of oxygen toxicity. Start the procedure
to terminate the dive.
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4.4.12 Missed decompression stop
alarm
If in the presence of a required decompression stop you ascend more than
0.5m/2ft above the required stop, the A2
will indicate an alarm: MISSED DECO.
This will continue for as long as you stay
0.5m/2ft or more above the required stop.
4.4.14 MB-level reduction warning
When diving with an MB-level higher than
L0 and in the presence of MB-level stops,
if you ascend more than 1.5m/5ft above
the deepest required MB-level stop, the A2
reduces your MB-level to the next possible
level. The display will show the new active
MB-level. You can set your A2 to warn you
when this happens.
English
WARNING
Violating a mandatory decompression obligation
may result in serious injury or fatal issue.
4.4.13 MB-level stop ignored
When diving with an MB-level higher than
L0 and in the presence of MB-level stops,
the A2 can warn you if you reach a depth
shallower than the deepest required MBlevel stop, therefore allowing you to avoid
missing the required stop.
4.4.15 Ascent rate alarm
The A2 employs a variable ideal ascent
rate. Its value ranges from 3 to 10m/min
(10 to 33ft/min) and the actual breakdown
by depth range is listed in the table below.
DEPTHASC SPEED
mftm/minft/min
00310
2.585.518
620723
12407.725
18608.227
23758.628
311018.929
351159.130
391289.431
441449.632
501649.832
1203941033
If you ascend too quickly, the resulting
pressure reduction could lead to
microbubble formation. If you ascend too
slowly, the continued exposure to high
ambient pressure means you will continue
loading some or all of your tissues with
nitrogen.
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If the ascent rate is greater than 110% of
the ideal value, the SLOW DOWN alarm is
shown.
4.4.16 SOS
If you stay above a depth of 0.8m/3ft for
more than 3 minutes without observing a
mandatory decompression stop, the A2 will
switch into SOS mode. Once in SOS mode
the A2 will lock up and will be inoperable as
a dive computer for 24 hours. If it is used
for diving within the 24 hours of an SOS
lock, it will automatically switch to gauge
mode and provide no decompression
information.
SOS in Gauge
mode
SOS in Scuba
mode
4.4.17 Low battery alarm
During the dive A2 will alert you if the
battery level is getting critically low. This
means you need to start the procedure to
terminate the dive, as there is not enough
energy in the battery to ensure the proper
functions and the computer may fail. Some
functions like backlight and audible alarms
are no longer available.
WARNING
Do not start a dive if the battery symbol is
blinking on the watch mode. The computer
may fail to function during the dive and this
could lead to serious injury or fatal issue.
4.4.18 Pressure signal
If the A2 receives no signal from the transmitter
for 70 seconds, an audible sequence goes off
and the message BAD SIGNAL appears on
the display for 12 seconds. After 30 seconds
without receiving signal the A2 emits another
audible sequence and the message SIGNAL
LOST appears on the display, after which the
tank pressure is replaced with - - -.
60
WARNING
Violating a mandatory decompression obligation
may result in serious injury or fatal issue.
Serious injury or fatal issue may result if a diver
does not seek immediate treatment should any
signs or symptoms of decompression sickness
occur after a dive.
Do not dive to treat symptoms of decompression
sickness.
Do not dive when the computer is in SOS mode.
WARNING
In the event of a “signal lost” situation, all tank
pressure-related information on the A2 ceases
to be valid. In such a case, you must use a
backup instrument for pressure monitoring
and seek a safe ascent to the surface. Running
out of gas under water is dangerous and may
lead to severe injury or death by drowning.
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4.4.19 RBT = 0 min
If the amount of bottom time you have
left at your current depth reaches 0, the
following alarm will be triggered:
In the event of a “signal lost” situation, all
tank pressure-related information on the
A2 ceases to be valid. In such a case, you
must use a backup instrument for pressure
monitoring and seek a safe ascent to the
surface. Running out of gas under water is
dangerous and may lead to severe injury or
death by drowning.
4.4.20 Half tank warning
If you have enabled the half tank warning,
the below display will be shown when
the selected tank pressure is reached.
Refer to chapter 3.3.5 Setting the half tank warning to learn how to enable this
warning.
4.4.21 Tank reserve alarm
Reaching the preset tank reserve pressure
triggers an alarm. In the RBT calculation
the tank reserve pressure is dening the
complete used tank. The reserve pressure
should still be in the tank when surfacing.
NOTE: Refer to chapter 3.3.6 Setting
F
the tank reserve alarm to learn how
to enable this feature.
4.5 No-Dive warning
If the A2 detects a situation of increased risk
(due to potential microbubble accumulation
from previous dives or a CNS O2 level above
40%), the NO DIVE symbol will appear to
advise you against performing another dive
right away. The suggested time interval
that you should wait prior to diving again
is shown in the top left section of the dive
mode display.
You should not undertake a dive as long
as the no-dive warning is displayed on
the computer screen. If the warning is
prompted by microbubble accumulation
(as opposed to CNS O
you dive anyway, you will have shorter nostop times or longer decompression times.
Moreover, the duration of the microbubble
warning at the end of the dive can increase
considerably.
over 40%) and
2
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4.6 No-Fly time
The no-y time is the time during which
an exposure to the reduced pressure
(equal to ascending at higher altitudes)
inside the cabin of an airplane could cause
decompression sickness, as calculated by
the decompression model in the computer.
The no-y symbol with countdown timer
is shown in the top right section of the
dive mode display until the restriction is
completed.
4.7 Diving with MB-levels
Microbubbles are tiny bubbles that can
build up inside a diver’s body during a dive
and normally dissipate naturally during an
ascent and on the surface after a dive. Dives
within no-stop times or the observance of
decompression stops do not prevent the
formation of microbubbles in the venous
blood circulation.
Dangerous microbubbles are those
migrating into the arterial circulation.
The reasons for the migration from the
venous blood circulation to the arterial
circulation can be because of a build-up
of microbubbles collecting in the lungs.
SCUBAPRO has equipped the A2 with
technology to help protect divers from
these microbubbles.
With the A2 you can choose – according
to your specic needs – a MB-level that
will provide a level of protection from
microbubbles. Diving with MB-levels
includes additional ascent stops which
slow the ascent process, giving the body
more time to desaturate. This works
contrary to the formation of microbubbles
and may increase safety.
The A2 features 10 microbubble levels (L0L9). Level L0 corresponds to SCUBAPRO’s
well-known decompression model ZH-L16
ADT PMG and does not require additional
stops due to microbubble formation.
Levels L1 to L9 offer additional protection
from microbubble formation, with level
L9 offering the highest level and most
protection.
Similar to the display of information during
decompression dives or dives within nostop time, the A2 displays the depth and
duration of the rst level stop as well as the
total time of ascent as soon as the MB nostop time has run out. As the MB no-stop
time is shorter than the ordinary no-stop
time, you will be required to perform a stop
sooner than a diver using level L0.
If you ignore a required stop, the A2 will
simply step down to a lower MB-level. In
other words, if you choose level L8 prior
to the dive, and during the dive you ignore
the L8’s recommended stops, the A2 will
automatically adjust the setting to level L7
or lower.
Comparison of dives with MB-level L0
and level L9:
When two A2 dive computers are used
simultaneously, with one unit set to a MBlevel of L9 and the other to a MB-level of
L0, the no-stop time for the L9 unit will be
shortened and more stops will be required
before the L9 diver has the same obligation
of a decompression stop as the L0 diver.
These additional stops help dissipate
microbubbles.
Depth
Time
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4.8 PDIS (Prole Dependent
Intermediate Stop)
4.8.1 Introduction to PDIS
The main purpose of a dive computer is to
track your nitrogen uptake and recommend
a safe ascent procedure. Diving within the
so-called no-stop limits means that at the
end of the dive you can ascend directly to
the surface, albeit at a safe ascent rate,
while for dives outside of the no-stop limit
(so-called decompression dives), you must
perform stops at certain depths and allow
time for excess nitrogen to be expelled
from your body before nishing the dive
and re-surfacing.
In both cases, it can be benecial to stop
for a few minutes at an intermediate depth
between the maximum attained depth
during the dive and the surface or, in case
of a decompression dive, the rst (deepest)
decompression stop.
An intermediate stop of this kind is benecial
as soon as the ambient pressure at that
depth is low enough to ensure that your
body is predominantly off-gassing nitrogen,
even if under a very small pressure gradient.
In such a situation, you can still cruise along
the reef and enjoy the dive while your body
gets a chance to slowly release nitrogen.
In recent times, so-called “deep” stops
have been introduced in some dive
computers and tables, dened as half
the distance from the dive’s maximum
depth and the surface (or the lowest
decompression stop). Spending 2 or 15
minutes at 30m/100ft would result in the
same deep stop at 15m/50ft.
With PDIS, as the name suggests, the A2
interprets your dive prole and suggests
an intermediate stop that is a function of
your nitrogen uptake so far. The PDI stop
will therefore change over the course of the
dive to reect the continuously changing
situation in your body. Along the same lines,
PDIS will account for the accumulated
nitrogen from previous dives; hence,
PDIS is also repetitive-dive dependent.
Conventional deep stops completely ignore
these facts.
The following gure quanties the extent
of PDIS and illustrates its dependence on
cumulative nitrogen uptake for 2 sample
dive proles. This gure also demonstrates
the conceptual difference between PDIS
and the rather rudimentary “deep” stops.
Specically, the gure compares 2 dive
proles to a maximum depth of 40m/132ft
that are otherwise very different.
Prole 1 stays at 40m/132ft for 7 minutes,
then ascends to 30m/100ft for 3 minutes,
followed by 12 minutes at 20m/65ft. Prole
2 stays less than 2 minutes at 40m/132ft,
then ascends to 21m/69ft and stays
there for 33 minutes. Both dive proles
are no-stop dives to the limit of entering
decompression.
The solid line represents the PDIS depth as
displayed on the computer screen during
the course of the dive for prole 1, the
broken line represents the PDIS depth as
displayed on the computer screen during
the course of prole 2. One can see that the
displayed PDIS depth increases as more
nitrogen is accumulated in the body, but
does so very differently in the 2 dives due
to the different exposure in the 2 proles.
The PDI stop is carried out at 25 minutes
for prole 1 and at 37 minutes for prole 2,
followed by the safety stop at 5m/15ft.
The line made up of small solid dots, on
the other hand, represents the depth that
would be displayed by a computer following
the conventional deep stop method, and it
would be the same for the 2 dive proles.
Deep stops completely ignore any facts
about the dives themselves aside from max
depth.
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8min16min24min32min40min48min
DIVE TIME
10m
20m
30m
40m
DEPTH
PDIS Prole 1
Deep Stop
Dive Prole 2
PDIS Prole 2
Dive Prole 1
4.8.2 How does PDIS work?
The mathematical decompression model in
the A2, called ZH-L16 ADT MB PMG, tracks
your decompression status by dividing
your body into 16 so-called compartments
and mathematically following the uptake
and release of nitrogen in each with the
appropriate laws of physics. The various
compartments simulate parts of your body
such as central nervous system, muscles,
bones, skin and so on.
The depth of the PDI stop is calculated as
that at which the leading compartment for
the decompression calculation switches
from on-gassing to off-gassing, and the
diver is advised to perform a 2-minute
stop above the displayed depth (this is the
opposite of a decompression stop, where
you are asked to remain just beneath the
displayed depth). During this intermediate
stop, the body is not taking up any more
nitrogen in the leading compartment, but
rather releasing nitrogen (though under
a very small pressure gradient). This,
combined with the relatively high ambient
pressure, inhibits bubble growth. It should
be noted that the 4 fastest compartments,
up to 10-minute half-times, respectively, are
not considered for the determination of the
PDI stop depth. This is due to the fact that
these compartments are only “leading” for
Safety Stop
PDI Stop
very short dives, for which an intermediate
stop is not required at all.
NOTE: The PDI stop is not a mandatory
F
stop, and it is NOT a substitute for the
3- to 5-minute safety stop at 5m/15ft.
WARNING
Even when performing a PDI stop, you still
MUST perform a safety stop at 5m/15ft for 3
to 5 minutes. Performing a 3- to 5-minute stop
at 5m/15ft at the end of any dive remains the
best thing you can do for yourself.
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4.8.3 Diving with PDIS
When the calculated PDI stop is deeper
than 8m/25ft, the A2 shows it on the display
and continues to do so until you reach the
displayed depth during an ascent. The
displayed value changes during the dive as
the A2 tracks the uptake of nitrogen in the
16 compartments and updates the PDIS
depth accordingly to reect the optimum at
all times.
During a no-stop dive, as soon as you
reach that depth during an ascent, a
2-minute countdown will appear.
You can have one of these 3 situations:
• You have spent 2 minutes within
3m/10ft above the indicated depth. The
countdown timer disappears and you
have successfully completed the PDIS.
• You have descended more than
0.5m/2ft below the PDIS. The
countdown timer disappears and will
reappear again, starting at 2 minutes,
the next time you ascend to the PDIS
depth.
• You have ascended more than 3m/10ft
above the PDIS. The PDIS value and
countdown timer disappears and PDIS
has not been performed.
NOTE: The A2 issues no warnings
F
relating to a missed PDI stop. When
diving with MB-levels, PDIS follows
the same rules as described above.
MB-levels, however, introduce stops
earlier and deeper than the L0 base
algorithm. As such, the PDIS display
may be delayed and, for certain dives,
it may not be displayed at all. This,
for example, would be the case for a
shallow dive with air (21% oxygen) and
a MB-level L5.
4.9 Altitude diving
4.9.1 Altitude warning after a dive
Climbing to altitude is similar to starting an
ascent from a dive: you expose your body
to a lower partial pressure of nitrogen and
you start off-gassing. After a dive, given the
higher nitrogen loading in your body, even
reaching an otherwise negligible altitude
can potentially cause decompression
sickness. Consequently, the A2 constantly
monitors the ambient pressure and uses it
to evaluate your nitrogen loading and offgassing. If the A2 notices a drop in ambient
pressure not compatible with your current
nitrogen loading, it will activate a warning
(altitude symbol starts blinking) to alert you
of a potentially dangerous situation.
The A2 counts down remaining saturation
and indicates this on the “dive ready mode”
screen with the no-y time until the available
saturation is no longer dangerous during a
ight or when crossing over a mountain
pass.
The allowable altitude (beyond which the
A2 has computed to be incompatible with
your current nitrogen saturation levels) is
displayed below the no-y time and the
surface interval. Refer to chapter 2.3.2
Reading the altitude, barometric and
temperature values for more information.
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4.9.2 Altitude and the
decompression algorithm
Atmospheric pressure is a function of
altitude and weather conditions. This is an
important aspect to consider for diving,
because the surrounding atmospheric
pressure has an inuence on on-gassing
and off-gassing of nitrogen in your body.
The A2 divides the possible altitude range
into 5 classes that are illustrated in the
picture below:
Altitude Class
Elevation
Barometric
switch point
Dive computer
mode
GAUGE
(no deco data)
SCUBA
SCUBA
SCUBA
SCUBA
The altitude classes are approximate
elevations because the effect of weather
conditions can make the switch point
pressure occur at different levels.
WARNING
At the altitude class 4 or higher the A2
operates in GAUGE mode only (the mode will
switch automatically).
NOTE: You can check your current
F
altitude class and elevation in the
Altimtr menu.
NOTE: The A2 deals with altitude
F
automatically - it monitors the
atmospheric pressure every 60
seconds and if it detects a sufcient
drop in pressure, it does the following:
it indicates the new altitude range and,
if applicable, the prohibited altitude
range; it indicates the desaturation
time, which in this case is an
adaptation time to the new ambient
pressure. If a dive is started during
this adaptation time, the A2 considers
it a repetitive dive since the body has
residual nitrogen.
NOTE: A fast descent from mountains
F
or a fast rise in airplane cabin pressure
may activate the dive mode. The A2
will automatically detect and end this
“dive” after 12 hours, or you may
manually activate the check by a
press-and-hold of both +/UP and -/
DOWN buttons at the same time. This
kind of false dive will not be stored in
the A2 logbook.
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4.9.3 Prohibited altitude
Going to altitude, as well as ying after
diving, exposes your body to a reduced
ambient pressure. In a manner similar
to no-y time, the A2 advises you of the
safe altitudes you can reach after a dive,
and those which are not safe. If you have
to drive over a mountain pass to return
home after a dive, this information can be
quite important and you can check this
information in the planner.
The current altitude class is shown in
the middle on the bottom row and the
prohibited altitude is shown on the right. In
the example above, the diver is presently
at altitude class 2 and should not reach
altitudes above 4000m (class 4) within the
given interval of 2 hours and 30 minutes. By
increasing the interval time on the middle
row the allowed altitude increases due to
the desaturation caused by the time spent
at the current altitude class.
WARNING
If atmospheric pressure is below 610mbar
(altitude higher than 4000m/13300ft), no
decompression calculation is carried out by
the A2, and it will not start in SCUBA mode, but
in GAUGE mode. In addition, the dive planner is
not available at this altitude.
4.9.4 Decompression dives in
mountain lakes
In order to ensure optimal decompression
even at higher altitudes, the 3m/10ft
decompression stage is divided into a
2m/7ft stage and a 4m/13ft stage in
altitude ranges 1, 2 and 3.
If atmospheric pressure is below 610mbar
(altitude higher than 4000m/13300ft), no
decompression calculation is carried out
by the A2 (automatic GAUGE mode). In
addition, the dive planner is not available in
this altitude class.
4.10 Diving with Nitrox
Nitrox is the term used to describe
breathing gases made of oxygen-nitrogen
mixes with the oxygen percentage higher
than 21% (air). Because nitrox contains
less nitrogen than air, there is less nitrogen
loading on the diver’s body at the same
depth as compared to breathing air.
However, the increase in oxygen
concentration in nitrox implies an increase
in oxygen partial pressure in the breathing
mix at the same depth. At higher than
atmospheric partial pressures, oxygen
can have toxic effects on the human body.
These can be grouped into 2 categories:
1. Sudden effects due to oxygen partial
pressure over 1.4bar. These are not
related to the length of the exposure to
high oxygen partial pressure. Sudden
effects can vary and depend on the
exact level of partial pressure they
happen at. It is commonly accepted
that partial pressures up to 1.4bar are
tolerable during the active part of the
dive, and maximum oxygen partial
pressures up to 1.6bar during the
decompression.
2. Long exposure effects to oxygen
partial pressures over 0.5bar due to
repeated and/or long dives. These can
affect the central nervous system and
cause damage to lungs or to other vital
organs. Long exposures can be divided
between more severe Central Nervous
System effects and less dangerous
long-term Pulmonary Toxicity effects.
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The A2 treats high ppO2 and long
exposure effects in the following ways:
Against sudden effects: The A2 has
an MOD alarm set for a user-dened
ppO
max. As you enter the oxygen
2
concentration for the dive, the A2 shows
you the corresponding MOD for the dened
ppO2max. The default value of ppO2max
from the factory is 1.4bar. This can be
adjusted to your preference between 1.0
and 1.6bar. It can also be turned off. Please
refer to chapter 3.3.1 Setting gas oxygen content for more information on how to
change this setting.
Against long exposure effects: The A2
“tracks” the exposure by means of the
CNS O
clock. At levels of 100% and higher
2
there is risk of long exposure effects, and
consequently the A2 will activate an alarm
when this level of CNS O2 is reached. The
A2 can also warn you when the CNS O2
level reaches 75%. Note that the CNS
O2 clock is independent of the value of
ppO2max set by the user. CNS O2 75%
warning and CNS O2 100% alarm can
be activate during a dive (see chapters
4.4.8 CNS O2 warning (over 75%) and
4.4.9 CNS O2 alarm (100%) for more
information), whereas the remaining CNS
O2 value after a dive is shown in the “ready
to dive” display in the left side of the bottom
row (in the below display this is 56%).
NOTE: For oxygen concentrations of
F
80% and higher, the ppO2max is xed
at 1.6bar and cannot be changed.
4.11 Diving in GAUGE mode
When the A2 is set to GAUGE mode,
it will only monitor depth, time, and
temperature, and will not carry out any
decompression calculations. You can only
switch to GAUGE mode if the computer
is completely desaturated. All audible and
visual warnings and alarms, other than the
low battery, max depth and max dive time
are turned off.
WARNING
Dives in GAUGE mode are performed at your
own risk. After a dive in GAUGE mode you must
wait at least 48 hours before diving using a
decompression computer.
When on the surface in GAUGE mode,
the A2 will show neither the remaining
desaturation time nor the CNS O
It will, however, display a surface interval up
to 24 hours and a 48-hour no-y time. This
no-y time is also the time during which you
cannot change the dive mode.
% value.
2
68
The CNS O2 clock increases when the
oxygen partial pressure is higher than 0.5bar,
and decreases when the oxygen partial
pressure is lower than 0.5bar. Hence, while
on the surface breathing air you will always
be decreasing the CNS O2 clock. During the
dive, the depth at which 0.5bar is reached
for various mixes is as follows:
Air: 13m/43ft
32% O
: 6m/20ft
2
36% O
: 4m/13ft
2
The GAUGE mode surface display after a
dive shows the dive time in the top row.
In the middle row the timer is running
from the dive start or last manual restart.
In the bottom row the water temperature
is shown. After a 5-minute timeout the
display changes to GAUGE mode ready to
dive menu.
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During a dive in GAUGE mode, the A2
displays depth and dive time at the top
row, a timer in the middle and water
temperature at the bottom row. The timer
can be paused and restarted by a pressand-hold of the +/UP button. When the
timer is paused, it can be reset to zero by
pressing-and-holding the -/DOWN button.
The alternative displays in the middle can
be scrolled through by pressing the +/UP
or -/DOWN buttons.
NOTE: For more information about the
F
conguration of the dive displays in
GAUGE mode, please refer to chapter
4.1.2.2 GAUGE mode display
selection.
4.12 Diving in APNEA mode
The A2 measures the depth in APNEA
mode every 0.25 seconds to ensure the
precise maximum depth. In the logbook
the data is saved in 1-second intervals.
In APNEA mode it is also possible to start
and stop the dive manually with a pressand-hold of the -/DOWN button. This way
you can use the A2 for static Apnea dives,
where a normal dive start depth of 0.8
meters will not start a new dive.
Apnea mode at the surface after an
immersion shows the maximum depth,
water temperature and the amount of
repetitive dives. The surface interval is
counted in the middle of the screen.
By pressing the +/UP or -/DOWN buttons
from the surface interval display the skin
temperature (37°C) and the heart rate
values (115 bpm), the maximum depth (4m)
and duration (01.13 min) of the last dive
and the total duration of the current Apnea
exercise (00:04) are shown.
The displays during the dive in Apnea mode
show skin temperature, heart rate values,
current dive time, depth, water temperature
and number of repetitive dives of the
current session.
The alternative displays in the middle can
be scrolled through by pressing the +/UP
or -/DOWN buttons.
The displays in APNEA mode are the
following:
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Elapsed dive time
Current depth
Skin temperature
4.13 Diving with CCR mode
The CCR (Closed Circuit Rebreather)
system is probably older than the Open
Circuit SCUBA system because the
basic operating principle with manual
control didn’t require a highly reliable
regulator system. The CCR system also
uses the gas more efciently than an
open loop system, because the oxygen
is added to the breathing loop only as
needed. Respectively, the carbon dioxide
generated by the body is bound to calc
at the scrubber. As a side effect the CCR
system is nearly bubble-free, which can be
benecial when engaged in photography
or observing shes underwater. In the CCR
system the breathing gas ppO2 (partial
pressure of the oxygen) is kept constant.
The CCR system itself takes care of this.
Compared to an open loop system the
constant ppO
mix at different depths. For example, a
setting of 1.0bar is comparable to an
ppO
2
open loop 50% nitrox mix at a depth of 10
meters in salt water.
converts to a variable nitrox
2
70
Heart rate
As with Gauge mode, the A2 in Apnea
mode doesn’t carry out any decompression
calculations. You can only switch to
APNEA mode if the computer is completely
desaturated. Also the A2 is locked in the
APNEA mode for 12 hours after shallower
than 5m dives and after deeper dives the
lock period is 24 hours.
WARNING
All rebreathers require unit specic education
before using them. Get the proper certications
and follow manufacturer recommendations
and procedures when diving with a rebreather
unit. Deviations may lead to severe injury or
death.
In CCR mode the display information shows
the ppO
oxygen concentration of the tanks T1-T8.
You can scroll through these displays with
the +/UP or -/DOWN buttons. The lower left
section of the display shows the O
the diluent tank and in the upper section
of the display the current depth and the
elapsed dive time are shown. To manually
access the displays in CCR mode, pressand-hold the SEL/ESC button.
F
setpoints (SP1 and SP2) and the
2
value of
2
NOTE: To conrm a switch from SP1
to SP2 (or the other way around),
press SEL/ESC in the respective
screen.
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English
Diving in CCR mode
If the switch between SP1 and SP2 was
not successful, the A2 will display the
following message:
The SP switch depth is suggested by
the dive computer the same way the
gas switches are suggested in open
circuit mode (predictive gas switching).
The switch points are determined by the
equivalent oxygen contents in open circuit
mode. So, the switch point is reached on
the way down when the equivalent content
of the gas at that depth reaches the diluent
level. For example, with a SP1 of 0.5bar
O
2
of the air diluent the depth would be
approximately 13.8m/45.3ft in salt water.
4.14 Diving with Sidemount
mode
In sidemount diving there are normally
two tanks and two regulators, each set
mounted independently on each side of the
diver.
Independent redundant gas delivery
systems should be drawn down equally,
in small steps, so in case one system fails
the other system has maximum reserves
to complete the dive. When the A2’s
sidemount mode is enabled (ON) and the
switching pressure is dened (see chapter
3.2.2.5 Enabling Sidemount mode), the
two tank pressures screen can be selected
during the dive in the middle of the screen
and it looks like the following display:
When the selected pressure difference (in
the situation below 20 bar) between the
tanks is reached, A2 is proposing to switch
to the higher pressure tank.
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Conrm the tank switch with a press of the
SEL/ESC button.
The active tank pressure is always shown in
the bottom right corner of the display.
When the tank with the higher pressure is
selected, there is no arrow indicator for the
switch.
NOTE: For proper operation of the
F
sidemount mode, both tanks must
be equipped and paired with a
transmitter.
NOTE: The Sidemount mode can be
F
used for backmount independent twin
tank diving as well.
4.15 Diving with multiple gas
mixtures
The A2 is equipped with the ZH-L16
ADT MB PMG algorithm. PMG stands for
Predictive Multi Gas, meaning that when
you program more than one gas mixture,
the A2 will predict the switch to the higher
oxygen concentration gas at the depth
that you specied and alert you at all times
with a comprehensive decompression
schedule of all the gas mixtures that you
programmed.
In other words, you get full credit at any
point during the dive for all the extra gas
mixtures that you are carrying with you.
NOTE: See chapter 3.2.2.6 Enabling
F
PMG mode to learn how to enable
this mode on your A2
WARNING
VERY IMPORTANT!
• Diving with multiple gas mixtures represents
a much higher risk than diving with a single
gas mixture, and mistakes by the diver may
lead to serious injury or death.
• During dives with multiple gas mixtures,
always make sure you are breathing from
the tank that you intend to use. Breathing
from a high oxygen concentration mix at the
wrong depth can kill you.
• Mark all your regulators and tanks so
that you cannot confuse them under any
circumstances.
• Before each dive and after changing a tank,
ensure that each gas mixture is set to the
correct value for the corresponding tank.
• Get the proper training and certications to
make multi-gas dives prior to making them
by yourself.
The A2 enables you to use up to 8 gas
mixtures during the dive.
• For oxygen concentrations of 80% and
higher, the ppO
and cannot be changed.
• The MOD for tanks 2 through 8 are the
switch depths for those gases. This is
what the A2 uses for its calculations,
warnings and suggested switch points.
• When diving with more than 1 gas
mixture, the nitrox reset time function
(described in the chapter 3.3.3 Nitrox reset time) has the following effect:
gas1 is set to 21% gases 2 through 8
are set to OFF.
max is fixed at 1.6bar
2
WARNING
Start breathing from the tank with the new gas
mixture before conrming a switch. Always
make sure you are switching to the intended
gas. Failure to do so may result in serious
injury or death.
The following sections about gas switching
are shown with 2 gas mixtures enabled.
However, more than two mixes enabled are
working similarly.
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Diving with 2 gas mixtures
4.15.1 Switching gas mixture during
the dive
During the ascent phase, when you reach
a depth corresponding to the MOD of a
gas other than the one you are currently
using, the A2 will suggest that you
perform the switch. An audible sequence
is played, and the message -> T2 (and
its O
content) appears on the display.
2
You have 30 seconds to respond to this
message; otherwise, the A2 will conclude
that gas 2 will not be used and adapt the
decompression schedule accordingly.
To conrm the gas switch, press the SEL/
ESC button. After conrming the switch,
the message SWITCH TO T2 remains on
the screen for approximately 5 seconds.
4.15.2 Switching back to a gas
mixture with lower oxygen
concentration
There may be situations where you
have to switch back to a tank with lower
oxygen concentration. This can happen,
for instance, if you want to descend again
below the MOD of the higher oxygen
concentration gas (T2), or if you have run
out of T2 gas during decompression. At
this point you can manually initiate the gas
switch by pressing-and-holding the SEL/
ESC button.
The A2 will display the message -> T1 and
its O
concentration. Press the SEL/ESC
2
button to conrm the switch or press +/UP
to select a different gas mixture.
4.15.3 Gas switch not carried out at
the planned depth
If you fail to conrm the gas change within
the 30 seconds of when the A2 suggests it,
the gas is excluded from the decompression
calculation and the decompression
schedule is adapted accordingly, basically
reecting the fact that you will nish the dive
without using the excluded gas.
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4.15.4 Delayed gas switch
You can catch up on a planned gas mixture
switch at any time by selecting the gas
manually. Press-and-hold the SEL/ESC
button to start the gas switch procedure.
The A2 will display for example -> T2 and
its oxygen concentration. This helps you
verify that you are performing a switch to a
safe gas. At this point you would press the
SEL/ESC button to conrm the switch. The
A2 will display the message SWITCH TO T2 and adapt the decompression schedule
accordingly.
4.15.5 Submerging below the MOD
after a gas switch
If after having switched to gas T2 you
inadvertently drop again below the MOD
for that mixture, the MOD alarm will
immediately be activated. In this case,
you would either switch back to gas T1 or
ascend above the MOD for gas T2.
4.16 Diving with Trimix mode
WARNING
VERY IMPORTANT!
• When breathing compressed air or EAN
Nitrox during a dive, the diver accepts a
certain level of risk. When breathing a Trimix
gas or other mix gases during a dive, the risk
level increases.
• We have used all relevant data and the
most recent hyperbaric research on Trimix
diving to bring the risk level of our Trimix
algorithm to the lowest possible acceptable
level. Nevertheless, we can in no way
guarantee that breathing Nitrox, Trimix,
mixed gases or compressed air during a dive
using our Trimix algorithm will eliminate or
prevent the risk of serious injury or death
from decompression sickness, oxygen
toxicity or some other inherent risk.
• The Trimix diver using our Trimix
algorithm on our dive computers should
be aware of the risk level and be willing to
accept that personal risk and bear the full
legal responsibility of such risks. If the diver
is not willing to accept those risks, including
serious injury or death, then he or she should
not dive with our Trimix mode.
• Never risk your life on only one source
of information. Eventually, every computer
has the potential to fail, so do not depend
exclusively upon it and always have a plan
for how to handle failures. Use a redundant
dive computer, carry backup tables and
depth/time instrumentation. If you make
riskier dives, obtain the proper training from
a recognized agency to gain the required
technical skills and experience needed for
this type of diving. Computer technology
is never a substitute for knowledge and
training.
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WARNING
Before performing trimix dives with the A2 you
should practice no-stop recreational diving
to become accustomed to the interface and
functions of the dive computer.
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4.16.1 Absolute Minimum Depth
Absolute Minimum Depth (AMD) and
Maximum Operating Depth (MOD) are
calculated from the oxygen content in the
mix. The ppO
divided by the oxygen fraction. The result
will be pressure, which is converted to
depth. The MOD is valid for all gases, while
the AMD is only applicable to a gas mix
where the oxygen fraction is less than air.
F
and Maximum Operating
Depth
that is given by the user is
2
NOTE: Air (21/0) gives a different MOD
than, for example, trimix 21/10. The
reason is, the A2 uses a more precise
value for the oxygen in the air, which is
20.7%.
WARNING
Altitude diving with hypoxic mixes requires
proper acclimatization. Adaptation to lower
ppO2 levels is a slow process requiring your
body to produce more red blood cells. The
adaptation time is personal and cannot be
directly calculated. Desaturation due to
pressure drop when arriving at altitude is
another factor (see chapter 4.9 Altitude diving).
4.16.2 Gas selection
In technical diving, especially with trimix
blends, the decompression efciency
becomes extremely important. Gas
mixes with high helium content and low
oxygen content are not well-suited for
decompression.
For example, where two decompression
mixes are, in most cases, enough when air
or nitrox is used as a bottom gas, in the
case of trimix, optimal off-gassing requires
more decompression mixes.
So, the PMG function shall be enabled
together with trimix as described in chapter
4.15 Diving with multiple gas mixtures
also applies to trimix diving.
Tank 1 is always the starting gas from the
surface. When you have set more than one
tank, you may change gases during the
dive manually or when the A2 suggests it.
The minimum O2 setting for tank T1 is 18%.
This is due to the limitation that a dive must
begin with gas 1. To ensure an adequate
supply of oxygen to the body, the gas used
at the beginning of the dive must contain
enough oxygen (you can use a travel mix
or one of the decompression gases) as is
required for Tank 1.
The minimum O
than tank T1 is 8%.
setting for tanks other
2
WARNING
Heavy work while at the surface or at shallow
depths while breathing with less than a
21% oxygen fraction may cause a loss of
consciousness and lead to drowning.
WARNING
Low oxygen fraction settings may allow
greater MOD values. The dive computer cannot
evaluate your skills, experience or condition to
dive the MOD which is showing. Dive only at
depths that your certication allows.
The A2 calculates the maximum possible
helium fraction by subtracting the oxygen
fraction from 100%.
WARNING
Helium reduces the narcotic effect of the mix,
but does not remove it. At great depths, helium
may also cause an effect called “helium
tremors” or HPNS (High Pressure Nervous
Syndrome).
4.17 Setting bookmarks
With a press of the SEL/ESC button you
can set any number of bookmarks as
reminders of particular moments during
the dive. The bookmarks will appear on the
dive prole in SCUBAPRO LogTRAK.
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5. INTERFACES FOR
THE A2 AND AN
INTRODUCTION TO
LOGTRAK
5.1 Establishing Bluetooth
communication
The A2 can be connected via Bluetooth to
a desktop, laptop or handheld device for
downloading dive data, conguring dive
computer settings or uploading rmware
updates.
From the main menu, toggle down to
Bluetooth using the +/UP or -/DOWN
buttons. Press the SEL/ESC button.
At this point the A2 is ready for Bluetooth
communication. Bluetooth is active only
when this screen is displayed.
Once the code is accepted by the device
you want to connect to, the link is ready for
communication.
5.2 LogTRAK
LogTRAK is the software that allows the
A2 to communicate with various operating
systems. LogTRAK is available for Windows,
Mac, Android and iOS. In the following
section, Windows and Mac versions of
LogTRAK are represented. Android and
iPhone/iPad versions of LogTRAK operate
similarly but do not have all of the features
offered in the PC/Mac versions.
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To achieve Bluetooth communication with
another device, set the device you want
your A2 to communicate with (e.g. an iOS
or Android handheld device) to “scanning”
mode.
The rst time you do this will require
entering a pin code to ensure secure
communication. This pin code is shown on
the A2’s screen.
5.2.1 Connecting the A2 with
LogTRAK
To start the communication using Bluetooth:
1. Pair the A2 with the device where
LogTRAK is running.
2. Launch LogTRAK.
3. Check that the A2 is detected by
LogTRAK
Extras -> Options -> Download:
Choose “Bluetooth Low Energy” option.
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NOTE: The A2 has a timeout of 5
F
minutes for a non-active Bluetooth
connection. After this interval the A2
will disable Bluetooth and return to
time and date mode.
NOTE: Desktop PC’s need a
F
generic Bluetooth Low Energy
(4.0) dongle, if there is no built in
Bluetooth 4.0 or newer module.
Windows version below 8.0 and
Mac computers require an external
Bluegiga BLED Bluetooth dongle.
5.2.2 Download dive proles
From LogTRAK, by selecting Dive ->
Download Dives you can transfer the A2
Logbook to your PC/Mac.
There are 3 main views, each showing a
specic part of your dive logs:
1. Prole, showing the graphical data of
the dive.
2. Details about the dive, where you
can edit, for example, the equipment
information.
3. Location, which shows your dive site
on the world map.
The selection tabs for views are found
along the left side of the main window.
English
5.2.3 Reading computer information
By selecting Extras -> Read dive
computer settings, you can nd general
device information for your A2. Dive
warnings can be enabled or disabled in this
menu by ticking the boxes found on the left
section of the “Warning audible” window.
By ticking the box “use PC-Time” and
selecting “Write” you can easily update
your current time and date.
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5.2.4 Writing owner information
with LogTRAK
Owner information can be registered in
the Extras -> Read dive computer settings-> Personalization section.
5.2.5 Setting units in LogTRAK
You can set your choice of units in your
A2 or on your PC by using the following
LogTRAK personalization section:
Extras-> Options-> Personalization
5.2.6 Updating your A2
In order to update the operating software
on your A2 dive computer, you need to
download the latest software package for
your A2 from the SCUBAPRO website and
store the .swu le locally.
To perform a software update, select the
menu Firmware upload from LogTRAK.
A le selecting pop-up window will appear.
Select the location where you have stored
the .swu le.
NOTE: The A2 will check the battery
F
status before the update process.
If the battery level is too low, the
software update cannot be started. In
order to update your A2, the battery
must be replaced rst.
Once the Bluetooth connection was
established and the new software version
has been selected, the transfer will start.
The A2 shows the transfer status on the
display with a progress bar.
78
After successful software download the A2
starts the reprogramming automatically.
Basic personal details about the user can
be shared in the Extras-> Options-> User info section.
Once the new software has been
programmed, the A2 will complete a few
internal checks and perform a reboot.
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After a successful update the A2 will
display the message “Software OK”. This
message can be cleared by a short press
of the SEL/ESC button. After this your A2 is
again ready for normal use.
NOTE: If the A2 detects any problem
F
during the transfer, programming or
software checks, an error message
will appear on the display. In case of
an error, switch off other Bluetooth or
WLAN devices from nearby and bring
your A2 closer to transmitting device.
In case of reoccurring error, check the
SCUBAPRO website or contact your
local SCUBAPRO service center.
You can check the current software version
of your A2 in the menu: Settings -> User
-> Service. For checking the last service
date press the +/UP button and the
following screen will be displayed:
NOTE: LogTRAK doesn’t have
F
a rmware upload module in all
operating systems, in Android this
function looks like in the screenshot
below.
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6. A2 ACCESSORIES
6.1 Wireless high pressure
transmitter
The A2 supports wireless tank pressure
using Smart series transmitters. With the
PMG function enabled you can use up to 8
transmitters with your A2.
Additional transmitters can be purchased
separately from your authorized
SCUBAPRO dealer.
NOTE: There are 3 generations of
F
Smart transmitters: Smart, Smart+
(longer distance) and Smart+ LED.
The A2 is compatible with all of these
versions.
6.2 Skin temperature heart
rate belt
The SCUBAPRO heart rate belt features a
patented skin temperature measurement
and transmission that is supported by the
A2. The proper positioning for wearing a
HR belt is shown below. Adjust the strap
so that it is comfortable to wear but snug
enough so that it stays in place. When
wearing a dive suit the HR belt must be
directly against the skin. Moisten the
electrode areas if your skin is dry or when
using a drysuit.
You must enable the heart rate function in
your A2. Refer to chapter 3.1.1.1 Workload
for instructions on how to do this.
After a dive rinse the heart rate belt in fresh
water, dry it and store it in a dry place.
For HR belts tted with a battery cap, it is
recommended that the battery be changed
by an authorized SCUBAPRO dealer.
Check the operating conditions and depth
rating of the HR belt from the unit or its
package.
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7. TAKING CARE OF
YOUR A2
7.1 Changing the watch strap
The watch straps of the A2 can be removed
and replaced by unscrewing the Torx
screws at the corners of the watch body.
Different types of watch straps are available,
like the nylon NATO type strap, linked metal
strap and swiveled silicon strap.
7.2 Display protection foil
You can protect your A2’s glass face with a
SCUBAPRO display guard. This foil can be
easily replaced if damaged.
NOTE: If air bubbles get stuck
F
underneath the protection foil when
placing it on your A2’s glass face, do
not try to remove them as the water
pressure will eliminate them after the
rst dive.
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7.3 Technical information
Operating altitude:
Sea level to approximately
4000m/13300ft.
Max operating depth:
120m/394ft; resolution is 0.1m until
99.9m, and 1m at depths deeper than
100m. Resolution in feet is always 1ft.
Accuracy complies with EN13319 and
ISO 6425.
Decompression calculation range:
0.8m to 120m / 3ft to 394ft.
Clock:
Quartz clock; time, date, dive time
displays up to 99 minutes and 59
seconds, and in minute steps up to
999 minutes.
Oxygen concentration:
Adjustable between 8% and 100%.
Helium concentration:
Adjustable between 0% and 92%.
Operating temperature:
-10C to +50C / 14F to 122F.
Power supply:
Lithium type CR2450 battery.
Operation time with a fresh battery:
Up to 2 years. Actual battery operation
time depends primarily on the
operational temperature and backlight
settings, but also on many other
factors.
Bluetooth
®
transceiver:
Operating frequency 2402-2478 MHz,
max power < 3 dBm, connection
range approx. 2m.
7.4 Maintenance
The A2’s depth accuracy should be veried
every 2 years by an authorized SCUBAPRO
dealer. The last service date can be
checked from the main menu: Settings ->
User -> Service.
The tank pressure gauge and the parts of
this product used to measure tank pressure
should be serviced by an authorized
SCUBAPRO dealer every other year, or
after 200 dives (whichever comes rst).
Aside from that, the A2 is virtually
maintenance-free. All you need to do is
rinse it carefully with fresh water after each
dive and change the battery when needed.
To avoid possible problems with your A2,
the following recommendations will help
assure years of trouble-free service:
• Avoid dropping or jarring your A2.
• Do not expose your A2 to intense, direct
sunlight.
• Do not store your A2 in a sealed
container; always ensure free ventilation.
• If there are problems with the water
contacts, use soapy water to clean your
A2 and dry it thoroughly.
• Do not use silicone grease on the water
contacts!
• Do not clean your A2 with liquids
containing solvents.
• Check the battery capacity before each
dive.
• If the battery warning appears, replace
the battery.
• If any error message appears on
the display, take your A2 back to an
authorized SCUBAPRO dealer.
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7.5 Replacing the battery
in the high pressure
transmitter
The following parts of the transmitter are
shown in the drawing below:
1. Transmitter cap screws.
2. HP port O-ring.
3. Main O-ring.
4. CR 2/3 AA battery.
5. Transmitter cap.
To change the battery in the high-pressure
transmitter:
1. Dry the transmitter with a soft towel.
2. Open the screws.
3. Replace the main O-ring (replacement
rings are available from your authorized
SCUBAPRO dealer).
4. Remove the empty battery and recycle
it in an environmentally friendly way.
5. Insert the new battery. Note the
polarity, “+” is marked on the body. Do
not touch to poles or contacts with
bare ngers.
6. Close the screws.
7. Check the transmitter function and
housing sealing.
7.6 Replacing the battery in
Heart Rate Belt
The following parts of the Heart Rate Belt
are shown in the drawing below:
1. Battery cap
2. O-ring
3. CR2032
4. Heart Rate Belt body
To change the battery in the Heart Rate Belt:
1. Dry the Heart Rate Belt with a soft
towel.
2. Open the battery cap.
3. Replace the main O-ring (replacement
O-rings are available from your
authorized SCUBAPRO dealer).
4. Remove the empty battery and recycle
it in an environmentally friendly way.
5. Insert the new battery. Note the
polarity, “+” is marked on the body. Do
not touch to poles or contacts with
bare ngers.
6. Close the battery cap. (Note the correct
closing position mark).
7. Check the Heart Rate Belt function and
housing sealing.
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7.7 Warranty
The A2 has a 2-year warranty covering
defects in workmanship and functioning.
The warranty only covers dive computers
which have been bought from an authorized
SCUBAPRO dealer. Repairs or replacements
during the warranty period do not extend
beyond the warranty period itself.
Excluded from warranty coverage are faults
or defects due to:
1. Excessive wear and tear.
2. Exterior inuences, e.g. transport
damage, damage due to bumping and
hitting, inuences of weather or other
natural phenomena.
3. Servicing, repairs or the opening
of the dive computer by anybody
not authorized to do so by the
manufacturer.
4. Pressure tests which do not take
place in water.
5. Diving accidents.
6. Opening the A2 housing.
7. Commercial use.
8. Exposing the unit to chemicals which
include but are not limited to mosquito
repellents and sunscreen.
9. Repairing with unauthorized spare
parts.
10. Using any software or accessory
which is not supplied by the
manufacturer.
For European Union markets, the warranty
of this product is governed by European
legislation in force in each EU member state.
All warranty claims must be returned
with dated proof-of-purchase to an
authorized SCUBAPRO dealer. Visit
www.scubapro.com to locate your nearest
dealer.
7.8 Compliance
7.8.1 EU Radio directive
Hereby, Uwatec AG, declares that the radio
equipment type PAN1740 is in compliance
with Directive 2014/53/EU. The full text of
the EU declaration of conformity is available
from the ofcial SCUBAPRO importers in EU.
7.8.2 Diving
A2 dive instrument is also compliant with
the European standard EN 13319: 2000
(EN 13319: 2000 – Depth gauges and
combined depth and time measuring
devices – Functional and safety
requirements, test methods).
7.8.3 FCC & ISED regulatory
notices
7.8.3.1 Modication Statement
Uwatec has not approved any changes or
modications to this device by the user. Any
changes or modications could void the
user’s authority to operate the equipment.
7.8.3.2 Interference Statement
This device complies with Part 15 of the
FCC Rules and Industry Canada licenseexempt RSS standard(s). Operation is
subject to the following two conditions: (1)
this device may not cause interference, and
(2) this device must accept any interference,
including interference that may cause
undesired operation of the device.
7.8.3.3 Wireless Notice
This device complies with FCC/ISED
radiation exposure limits set forth for an
uncontrolled environment and meets
the FCC radio frequency (RF) Exposure
Guidelines and RSS‐102 of the ISED
radio frequency (RF) Exposure rules. This
transmitter must not be co-located or
operated in conjunction with any other
antenna or transmitter.
The A2 contains TX FCC ID: T7V1740.
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7.8.3.4 FCC Class B Digital Device
Notice
This equipment has been tested and found
to comply with the limits for a Class B digital
device, pursuant to part 15 of the FCC
Rules. These limits are designed to provide
reasonable protection against harmful
interference in a residential installation.
This equipment generates, uses and can
radiate radio frequency energy and, if not
installed and used in accordance with the
instructions, may cause harmful interference
to radio communications. However, there
is no guarantee that interference will not
occur in a particular installation. If this
equipment does cause harmful interference
to radio or television reception, which can
be determined by turning the equipment
off and on, the user is encouraged to try to
correct the interference by one or more of
the following measures:
1. Reorient or relocate the receiving
antenna.
2. Increase the separation between the
equipment and receiver.
3. Connect the equipment into an outlet
on a circuit different from that to which
the receiver is connected.
4. Consult the dealer or an experienced
radio/TV technician for help.
7.8.3.5 CAN ICES-3 (B) / NMB-3 (B)
This Class B digital apparatus complies
with Canadian ICES-003.
English
Your dive instrument is manufactured
with high-quality components that can be
recycled and reused. Nevertheless, these
components, if not properly managed
in accordance with the regulations on
electrical and electronic equipment waste,
are likely to cause harm to the environment
and/or to human health. Customers living
in the European Union can contribute to
protecting the environment and health by
returning old products to an appropriate
collection point in their neighborhood in
accordance with EU Directive 2012/19/
UE. Collection points are provided by
some distributors of the products and
local authorities. Products marked with
the recycling symbol above must not be
disposed of in normal household waste.
7.9 Manufacturer
UWATEC AG
Bodenäckerstrasse 3
CH-8957 Spreitenbach
SWITZERLAND
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8. GLOSSARY
AMDAbsolute Minimum Depth, the depth where a mix can be started to be
used based on its oxygen content
AVGAverage Depth. Calculated from the beginning of the dive or from the
time of reset.
CCRClosed Circuit Rebreather. A breathing device that absorbs the
carbon dioxide of a diver’s exhaled breath to permit the recycling, or
“rebreathing,” of the unused oxygen content of each breath.
CNS O
2
Central Nervous System Oxygen toxicity.
DESATDesaturation Time. The time needed for the body to completely
eliminate any nitrogen taken up during diving.
Dive TimeThe time spent below a depth of 0.8m/3ft.
GasRefers to the main gas that is set for the ZH-L16 ADT MB PMG algorithm.
Local TimeCurrent time in the local time zone.
Max DepthMaximum depth attained during the dive.
MBMicrobubbles: Microbubbles are tiny bubbles that can build up in a
diver’s body during and after a dive.
MB-levelOne of 9 levels (L0-L9), provided by the A2’s ZH-L16 ADT MB PMG
algorithm.
MODMaximum Operating Depth. This is the depth at which the partial
pressure of oxygen (ppO
) reaches the maximum allowed level
2
(ppO2max). Diving deeper than the MOD will expose the diver to
unsafe ppO2 levels.
NitroxA breathing mix made of oxygen and nitrogen, with the oxygen
concentration being 22% or higher.
NO FLYMinimum amount of time a diver should wait before ying.
No-Stop TimeThe amount of time a diver can stay at the current depth and still
make a direct ascent to the surface without having to perform
decompression stops.
O
2
Oxygen.
O2%Oxygen concentration used by the A2 in all calculations.
PDISProle Dependent Intermediate Stop is an additional deep stop
which is suggested by the A2 at a depth where the 5th, 6th or 7th
compartment starts off-gassing.
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PMGPredictive Multi-gas. Lets you carry additional breathing gases in
addition to your main breathing gas.
ppO
2
Partial pressure of oxygen. This is the pressure of the oxygen in the
breathing mix. It is a function of depth and oxygen concentration. A
ppO
higher than 1.6bar is considered dangerous.
2
maxThe maximum allowed value for ppO2. Together with the oxygen
ppO
2
concentration, it denes the MOD.
Press-and-hold
The act of pressing-and-holding the button for 1 second before releasing.
RBTRemaining Bottom Time. The time you can spend at the current depth
and still have enough gas supply to make a safe ascent and reach the
surface with the tank reserve.
SidemountPractice of diving with two or more cylinders secured at the sides of the
body in line with the torso and without cylinders on the diver’s back.
SOS ModeThe result of having completed a dive without respecting all mandatory
decompression obligations.
SURF INT
Surface interval. The time that starts at the moment the dive is closed out.
Switch PointThe depth at which the diver plans to switch to a different oxygen mix
while using the multi-gas option.
TATTotal Ascent Time.
TrimixA gas mixture containing Oxygen, Helium and Nitrogen
UTCUniversal Time Coordinated. This is the primary time standard used
worldwide to regulate clocks and time. UTC correlates to your
location’s time zone through the use of offsets ranging from -12 to +14
hours.